Talk:Heavy water

Nuclear Proliferation
It seems to me that this section is not about heavy water so I have removed it. South Korea also possesses graphite-moderated reactors, as used by the United States, the United Kingdom, the USSR and France for their bomb programs (in fact it was stated in British Parliament that one of these had been built to the declassified blueprints for Calder Hall). A major part of the negotiations involving North Korean nuclear reactors have been to attempt to shut down all of these reactors. Dabbler 15:39, 22 Dec 2004 (UTC)


 * There is something very odd here, because things are not "built to ... blueprints", but rather, they are "built from blueprints" or "built according to blueprints". I am an engineer, and I want my workers to build things "according to" or "from" my blueprints, and not the other way around.98.67.163.173 (talk) 03:23, 19 January 2010 (UTC)

Abundance
Would someone care to explain this to me?

About one in 6000 hydrogen atoms is deuterium. (The nuclide table at http://atom.kaeri.re.kr/ton/ confirms this.) Under the assumption that the deuterium atoms are randomly distributed over the water molecules, one would expect about 1 in 6000 water molecules to be semiheavy (DHO), only 1 in about 36000000 heavy (D2O), and the rest light (H2O).

Yet the article states that heavy water occurs naturally in regular water at a proportion of roughly one part in 6,000. What's going on here? Are they trying to sell us semiheavy water as 'heavy' water? Or what?

– 2004-02-08


 * If 0.015% (nearer 1 in 6500) of H's are D's, then about 2 in 6500 (0.03%) of water molecules should have one D - i.e. be "Semi-Heavy" - not 1 in 6500 [1/6500 * 6499/6500 + 6499/6500 * 1/6500 = 1/3250.5]. As you say, 1 in 65002 or about 1 in 42 million should have two Ds, and be "Heavy".


 * Of course, the heaviest natural water is not ordinary D2O, but D218O, which weighs 22. The abundance should be 1/6500.1/6500.1/500 = about 1 in 21 billion. Not so low really; there's about a million trillion in the average glass of water... –220.237.78.234 2004-11-29

Toxicity
Next time I want to kill someone I'll make a note of this article. Seriously, maybe that excerpt is best left out.. If there has ever been a case of this, it would be nice to note, but suggesting it as a good way to poison someone may be a bit...non-encyclopediatic? - Reboot

It does not seem to be of great scientific interest. Perhaps it is useful to writers of fiction?


 * Heavy water would be an ideal poison for killing someone, since it is extremely unusual for forensic tests for it to be performed, and it would appear that the person was merely suffering from some mysterious illness. However, it is very expensive, and requires a government license to purchase, making this method of killing someone less attractive in practice.

I'm not sure that this would even be true. It would seem to me that some of the standard tests that would be used in case of unknown poisoning would have sufficiently odd results that would raise a lot of suspicions. An MRI would be almost totally blank - it's an NMR scan of the body, and D2O is used as a solvent in NMR because it doesn't show up, at all.


 * You would think this, but if forensics ran a mass spectrum to look for other toxins then the excess of deuterium would be blindingly obvious.
 * Blindingly obviously, how? Toxin mass spec only comes after HPLC or GC, and if the person has no "toxins" in them (drugs, etc) then all you're looking at is the standards you added. Nada. I have no idea if forensic tox mass spec uses any internal metabolite standards, but even that ought to be difficult to see with D. For one thing, D only exchanges with OH and NH2 hydrogens, and even then you're only going to get less than 50% exchange in what is probably a fairly high MW molecule. My bet is any low intensity double lines in a calibration metabolite would get ignored, because it's not in the toxin area of interest.
 * (On a different note, D2O does show up on NMR, just not on the region shown in proton NMR spectra) Gingekerr 20:18, 28 May 2006 (UTC)
 * That's basicly noted in the article, which doesn't say there's no signal, just that the signal isn't in the protium frequency. It's even a bit more clear in the deuterium wikiSbharris 21:13, 28 May 2006 (UTC)
 * And I thought the stuff was sufficiently radioactive that it would poison those around it without actually drinking it... Anyone have a clue on that?  I agree that if someone came into a hospital suffering from what looked like radiation poison that I'd like to think it would warrant further investigation other than "oh well he must have died from some mysterious illness...sigh....too bad...oh well, throw em in the box" -- Reboot


 * Pure heavy water is not radioactive, but I guess it becomes contaminated by radioactive decay products after it's been in a nuclear reactor. You're probably thinking of tritiated water (see tritium). -- Heron


 * In that case... Drink up :-) - Reboot

Hmmm. It seems to me that the suggestion that heavy water is toxic is a bit suspect. The ill effects are only felt if you drink nothing else. So long as you maintain a normal intake of ordinary, light water, you'll never be in danger of these supposed ill effects.

I say supposed because I doubt anyone has ever suffered them. Quite apart from the licensing aspects, last time I checked it was about 7 times the price of good whisky.

We don't regard nitrogen as toxic. But, if you breath nothing but nitrogen, you will die quite quickly. So similarly, we should not regard heavy water as toxic just because it won't sustain life in the same way that normal water will.

The same goes for Helium or Hydrogen. Neither is toxic. But breathing either of them will kill you.

Or am I missing something here? Andrewa 10:31 Mar 5, 2003 (UTC)

OK, with some foreboding I've had a go. Is this an unbiased discussion of the toxicity claims now, do you think? I've also added some other information. Andrewa 16:11 Mar 6, 2003 (UTC)

Hmmm. My comparison of the toxicity of Nitrogen to that of Heavy Water has been deleted from the article as an "improper" comparison, according to the summary: "(Deleted improper comparison: It was not said that one would die if started to use only pure D20. However if someone would die if s/he would breath only Nitrogen or Helium.)"

I think this editor has misunderstood the logic. No, nobody would die of drinking heavy water, or not quickly anyway. SO, it is even more ridiculous to suggest that heavy water is toxic than it would be to say that nitrogen (or hydrogen or helium) is toxic. QED.

So the comparison is relevant. I'm not sure how to decide whether it is "proper", but I found it helpful, and I think this deletion has pointlessly reduced the content of the article, even if only slightly. But obviously it could have been better expressed. I'll have a go sometime, unless someone else does first or successfully argues that it's not helpful content anyway. Andrewa 01:15 20 Jun 2003 (UTC)

Reinstated the comparison, hopefully more clearly. I think it's NPOV, but I admit it's very difficult to be so when the claims of toxicity are plainly ridiculous and politically motivated.

I think what the article says is still very gentle really! Andrewa 16:45 29 Jun 2003 (UTC)

I see the point... that is, while that poison... smells like almonds... can't think of name... cyanide! Cyanide is toxic; i.e. if you eat it, along with drinking like 10 cups of water, you'll still die. Whereas, if you drink some heavy water, but make sure to continue normally drinking light water, you'll be fine. ugen64 23:54, Nov 19, 2003 (UTC)

I agree with Andrewa, the comparison is a good one, I found it insightful. Pdbailey 16:55, 6 Nov 2004 (UTC)

To take it further - tap water will kill you if you fall in a bath of it and can't swim but is it toxic?.........Ordinary table salt is genuinely toxic - the lethal dose is about 2 Kg - but that doesn't stop us swimming in water, and putting salt on our food.

Any way, my question is, why did they have a heavy wter plant anyway - no-one had thought of building a bomb at the time, so what was the point of making heavy water - does it have other uses? David.andrews@wessexwater.co.uk

How universally true is it that eukaroytes don't thrive in D2O, as stated? I once left a Kleenex soaked in D2O and left it sealed in a plastic bottle to keep a D2O vapour over something. After a month or so it went black with something that looked suspiciously like pin mould, which being a fungi would be eukaryotic.Judge Nutmeg 05:14, 28 January 2007 (UTC)


 * Your observation may be a new scientific observation, but likely not. So far only bacteria have been reported grown in pure heavy water. I presume fungi have mitotic apparatus which would be screwed by the stuff, or they may be able to get enough normal water out of the air in the conditions you describe (even 30% normal H is enough to allow some simple eucaryotes to survive). Overall, I think the statement as it stands is likely to be correct. S  B Harris 06:26, 28 January 2007 (UTC)


 * First guess, exchange of hydrogen ion from the D2O with whatever the something was. But, if this was going to happen in a eukaryote, fungi would probably be a good place to look first! Also, given that bacteria can survive with 100% D for H replacement, its tempting to wonder if D2O tolerant, or even dependent, eukaryotes could be bred or engineered somehow. I'm not sure what the point would be, but it is an interesting concept anyways. Zaphraud 02:20, 26 July 2007 (UTC)

It must be remembered with any material that toxicity is dose-dependent. Today I picked up a bottle of SDS that actually had 'Toxic!' written on the side, and yet this compound is ubiquitous in consumer products such as toothpaste. Toxicity always relates to the level of risk - KCN is much more of a risk to work with than D2O as the likelihood of ingesting/inhaling enough cyanide to cause health problems is much greater in the event of an accident. --WhirlwindChemist (talk) 22:38, 30 September 2008 (UTC)

Norwegian infiltrators.
I heard on The History Channel it was a 7 man team not 12, does anyone know which is correct? Also they said one of the members of the team that stayed in Norway destroyed the ferry that was carry the heavy water on orders by the British (so technically he wouldn't be a "partisan"). — Preceding unsigned comment added by CorranH96 (talk • contribs) 03:26, 22 May 2004 (UTC)


 * Yes, it was a 12 man crew, and one of the members did later on destroy the ferry.. I am not sure about his name though, I do know that due to the large number of potential civilian causualties he got the order from British top-level command.


 * I removed (twice) comments about computer games and a link to "sabotage". They where inappropriate in the context. Teemu Ruskeepää 13:33, 31 October 2005 (UTC)

Germany and The Bomb
I heard on a documentary that during World War II, Germany believed that the creation of large amounts of heavy water was essential to make an atomic bomb. Does anyone know more about this? If you do, it may be a good addition to this article. — Preceding unsigned comment added by NoPetrol (talk • contribs) 01:52, 7 November 2004 (UTC)


 * I recall reading that the Germans goofed when they measured graphite, and thus rejected it as unsuitable. Don't have references.  pstudier 03:12, 2004 Nov 7 (UTC)

HDO
Surely you can isolate pure HDO from a sample using a mass spectrometer or centrifuge or similar mass discriminating device?--LukeSurl 23:12, 14 Apr 2005 (UTC)


 * The hydrogren atoms in water are in a state of rapid equilibrium: a hypothetical sample of pure HOD would become the equilibrium mixture in a fraction of a second. Shimmin 23:29, Apr 14, 2005 (UTC)


 * It is not stable. In water, a small fraction of the molecules are in the form H+ and OH-, and they change back and forth. Pure HDO would split up, and get mixed up, to form H20, D20 and HD0 according to the laws of probability. pstudier 23:37, 2005 Apr 14 (UTC)


 * The fraction of pure water that has split into H+ and OH- at any given time is incredibly low. It is one in 10^-7, as a matter of fact. However, I don't know anything about how quickly they recombine and are replaced by new pairs of H+ and OH-. The one part in 10^-7 is what gives pure water a pH of 7.0 98.67.163.173 (talk) 03:40, 19 January 2010 (UTC)

Senseless Sentence: HDO
This part doesn't make any sense:

"Semiheavy water, HDO, also exists, although not in pure form: a sample of water of average composition HDO actually contains 50 percent HDO and 25 percent each H2O and D2O."

It says that semiheavy water is called HDO and then it describes HDO as something composed from HDO and h20/d20. Can someone who knows what HDO is edit this? — Preceding unsigned comment added by 67.68.4.208 (talk) 06:35, 23 May 2005‎ (UTC)


 * it makes perfect sense if you think back to pH - percent hydrogen. Well, in this case pH is going to also involve pD, since the positive ion can either be D+ or H+, and the negative ion can also be OH- or OD-. Since the water molecule in pure liquid water is constantly splitting and recombining, it stands to reason that a mixture of 1 mole of H2O and 1 mole of D2O will soon recombine, giving some molecules of HDO. Likewise, if pure HDO is somehow created in a low-pressure vapor state, then condensed into a liquid, some concentration of it will become H+ OD- and some concentration of it will become D+ OH-, and recombination will occur, giving some D2O and some H2O. If all possibilities are equally likely, the suspected mixture at equilibrium will be 50/25/25 because HDO and DHO are technically the same thing ... Zaphraud 01:36, 26 July 2007 (UTC)
 * Pretty much correct, except that pH doesn't stand for percent hydrgen, but log10H+-- the p can stand for "log" although it's been claimed to stand for "pondus," "potentiel", "potenz", and "potential" in various languages. Perhaps. I'm not convinced that the convention to use "p" as log10 didn't come until AFTER pH had become a convention. See the article on pH for more. S  B Harris 02:50, 26 July 2007 (UTC)


 * The sentence, "Semiheavy water, HDO, also exists, although not in pure form: a sample of water of average composition HDO actually contains 50 percent HDO and 25 percent each H2O and D2O," does not make sense because of a lack of commas and a preposition, and might not make sense even when some are inserted. Here are some possibilities:
 * "Semiheavy water, HDO, also exists, although not in pure form: in a sample of water of average composition, HDO actually contains 50 percent HDO and 25 percent each H2O and D2O."
 * "Semiheavy water, HDO, also exists, although not in pure form: a sample of water, of average composition of HDO, actually contains 50 percent HDO and 25 percent each H2O and D2O." In this latter version, a wrong word was also chosen, and it should read:
 * "Semiheavy water, HDO, also exists, although not in pure form: a sample of water, of an average percentage of HDO, actually contains 50 percent HDO and 25 percent each H2O and D2O."
 * In any case, water of average composition contains nowhere near 50% HDO, and also nowhere near 25% D2O. In any of these versions, the sentence looks "busted".98.67.163.173 (talk) 03:57, 19 January 2010 (UTC)

The sentence I think meant the phrase: "A sample of water of average composition "HDO." In other words, HDO is the empirical formula for what's in the bottle, not the molecular formula. When that's the case, the bottle actually contains 3 substances with molecular formulas HDO, D2O, and H2O, in proportions given. The same would happen if you could some how fill the bottle with HDO one molecule at a time.  S  B Harris 04:07, 19 January 2010 (UTC)

Deuterium and Heavy Water should be merged!
— Preceding unsigned comment added by 85.65.241.138 (talk) 18:07, 7 July 2005‎ (UTC)

Not at all. This statement is similar to claiming that hydrogen and water should be merged. — Preceding unsigned comment added by Shaddack (talk • contribs) 17:58, 9 July 2005 (UTC)

Chemically the same
I am wary of this statement.

Acegikmo1 05:12, 25 July 2005 (UTC)


 * Isotopes of an element are, by definition, all chemically the same.


 * No, not by "definition." By definition they all have the same standard chemical symbol and element name, but none of that guarantees that their chemical properties will be the same, and in fact they aren't. Of course this difference is much more pronounced with the hydrogen isotopes.


 * They are different only in their mass, which is a physical property, and in that some isotopes may be unstable (radioactive), which is a nuclear property. (Digressing, it might be more accurate to say 'some isotopes may be stable', since there are many elements with no stable isotopes, and I'm not aware of any element with no unstable isotopes.)


 * Having said that, the statement you object to is less true for (compounds involving) the isotopes of hydrogen than it is for any other element's isotopes. This is because the mass ratios among 1H, 2H, and 3H are larger than for any other element, large enough to have measurable effects on certain chemical properties, primarily reaction rates.


 * Nope, most of deuterium's bio effect has nothing to do with "reaction rates" if they that you mean some kind of slow diffusion due to mass. Rather, the bond strengths for O-D, C-D, and so on differ by quite a lot. That's due to the very large difference in reduced mass in the Schroedinger equation (or appropriate LCAO/MO approximations) for the bond.Sbharris 19:49, 1 May 2006 (UTC)


 * Down in the middle of the article where it is talking somewhat clumsily about the negative health effects of saturating an organism with heavy water, that's what it means. But this is still a slight effect in chemical terms, so I don't think the statement in the lead should be changed; it might make sense to talk about it more in the body of the article.


 * Zack 21:30, 25 July 2005 (UTC)

I suggest that this should be changed. If the kinetics and the rates of reaction are different, and the actual biochemical effects are different, then saying that heavy water is chemically identical to normal water is simply incorrect, and the article should not make that statement in the introduction, regardless of what detail it goes into later.


 * It is correct to say that they are chemically identical, because 'chemically identical' means 'the same element'. Mass-based kinetic effects are not enough to make them chemically different.


 * Zack


 * Actually in the case of deuterium, they are. And it's not "kinetics" but "energetics."


 * This is an oddity, but I agree that kinetics are a part of chemistry and it is not fair to say that two things are chemically the same when they have different chemistry. It's fair to say that they are chemically similar, just not the same. For emphasis, the effect can be about a factor of six on a reaction rate, this is not small in my book
 * Pdbailey 03:40, 26 September 2005 (UTC)


 * I don't know how I can make it clearer. 'Chemically identical' is defined to ignore isotopic differences.


 * Perhaps in common use, but not among chemists. A chemist will tell you that different bond strengths means different chemical behavior, whether different symbol or not. The pH of D2O at 25 C is 7.4, not 7.0. That's chemistry, and it's not any chemistry which has to do with kinetics. Sbharris 19:49, 1 May 2006 (UTC)


 * The encyclopedia needs to use chemistry terminology the same way chemists do, even when that is awkward pedagogically. We could do a better job of explaining how hydrogen is a special case, and maybe I'll even get to it sometime soon, but this particular sentence is correct as it stands.


 * Zack 05:35, 27 September 2005 (UTC)

The statement is incorrect. These are not merely "mass based kinetic effects." The compounds are chemically distinct. Please refer to, e.g., Pharmacological uses and perspectives of heavy water and deuterated compounds, D.J. Kushner, Alison Baker, and T.G. Dunstall, Can. J. Physiol. Pharmacol., 77(2): 79-88 (1999).

Notably, there is a table of data concerning the difference in chemical properties:

Table 1. Some physical properties of heavy and light water (from Katz 1965).

Also, an a pair of statements concerning chemical bonding properties:

"Living systems exposed to D2O experience at least two sets of effects. One is a “solvent isotope effect,” because of the properties of D2O itself, and especially its effects on the structure of water and macromolecules. The second is the “deuterium isotope effect” (DIE), resulting from the ability of D2O to replace H with D in biological molecules. The C–D bond is about 10 times as strong as the C–H bond and more resistant to chemical or enzymic cleavage. Compounds with C–D bonds tend to remain stable in H2O indefinitely, and such compounds have been very widely used for isotopic studies. O–D, N–D, and S–D bonds are also stronger than the corresponding protonated forms, but the D in such bonds quickly exchanges with H in H2O (Katz 1965; Thomas 1971)."

Since light water and heavy water have distinctly different physical and chemical properties, and react with other compounds to produce compounds that have different physical and chemical properties, it is incorrect to claim that the substances are chemically the same. "Isotopes of an element are, by definition, all chemically the same" is true, if it is true at all, only when you are discussing elements and not compounds containing those elements. Heavy water is not an isotope of water.

DrWitty 00:51, 12 November 2005 (UTC)

Most sources I have seen put the boiling point closer to 101.4 including two of the sources cited in this article. --Phoenix Hacker 02:32, 31 March 2006 (UTC)

It all depends on what you mean by "chemically identical". D and H certainly have measurably different kinetics for many reactions, but there are thermodynamic differences too. In most cases the differences are small, for instance a phase boundary may move by a few degrees C, however in some cases the difference is large. There is a term "strong isotope effect" for the latter: in some cases you can have completely different phases that are thermodynamically stable for deuterated phases than those observed for non-deuterated phases. Of course, it is possible that the phase boundaries are just shifted below 0 Kelvin or moved around in pressure, so you don't see them at ambient pressure. But this itself is an interesting topic which is probably worthy of its own Wikipedia page.Judge Nutmeg 05:10, 28 January 2007 (UTC)

Kinetic and thermodynamics are being mixed up here. The C-D bond is not "10 times stronger than the C-H bond". The C-D bond strength is only a few percent stronger than the C-H bond, but this makes a big difference to the rate at which it reacts (see the Arrhenius equation). The difference in bond strength is due almost entirely to the zero point energy of vibration. For deuterium compounds the vibrational energy is lower so the amount of energy required to break the bond is higher. 64.28.142.10 (talk) 17:47, 3 November 2008 (UTC)

Israel and Heavy Water
I removed the section on Israel. The question where Israel got its heavy water to run the Dimona reactor on is better placed in an article like Israeli Nuclear Program and has nothing to do with the use or production the compound itself. Besides, it's lifted word-by-word from the Guardian. Pilatus 15:02, 10 August 2005 (UTC)

Norsk Hydro (Why did Norway have a Heavy water plant)
This text was inserted by an anonymous contributor in the middle of the Norway section. I've removed it from the article. Their text is in parentheses - everything else is context. Zack 19:26, 29 September 2005 (UTC)


 * In 1934, Norsk Hydro built the first commercial heavy water plant - (was it a heavy water plant, or in fact a hydrogen plant that made heavy water as a by-product? What was the point of heavy water before the atom bomb?)


 * They're good questions though (the contributor probably intended to post them on the talkpage rather than within the article text) Id like to know too. 213.40.217.126 (talk) 18:04, 5 December 2008 (UTC)


 * It should be clear that heavy water and heavy hydrogen have other uses besides in the nuclear reactor industry. For one thing, deuterium and heavy water were only discovered in late 1931, by a team lead by the American chemist Harold C. Urey, and in 1934, nobody knew much about what it was good for. That in itself was enough justication to produce significant quatities of it so that it could be experimented with. How would you find out what it is good for iy you don't have enough of it to test it in many different ways? Furthermore, it quickly seen that deuterium could be used as a "tracer" in biochemical experiments. You could water some plants with heavy water and then do tests to find out where the heavy hydrogen goes. Also, someone could (and did) replace some of the regular hydrogen in organic compounds, and then follow the path of the heavy hydrogen through large series of chemical reactions. Since deuterium is not radioactive, they had to generate large-enough samples of biochemicals to be able to use mass spectrometry to identify where the heavy hydrogen went in the chemical reactions in plants or simple animals. This kind of tracing was also done with oxygen-18 once that isotope was discovered. In the second half of the 20th Century, biochemists figured out how to use radioisotopes as tracers, and that is somewhat more convenient, since they could just used Geiger counters and scintillation detectors to follow the radioisotopes. In biochemistry, tritium, carbon-14, and perhaps nitrogen-15 and oxygen-17 were useful for these tracers among the light elements, and I believe that they have used radioactive isotopes of sulfur, sodium, potassium, magnesium, chlorine, phosphorus, and iron, too.98.67.163.173 (talk) 04:38, 19 January 2010 (UTC)


 * Do you have any actual sources to corroborate any of this speculation?


 * The Norsk Hydro Rjukan article states that the primary purpose of the Norsk facility was NOT to produce heavy water but to produce free hydrogen from the electrolysis of water (hence its co location with a power plant), which in turn was used to produce ammonia using the Haber process, which was used to make fertilizer. It appears that Norsk undertook this as a joint venture with ICI (Britain) and IG Farben (Germany). The heavy water was merely a byproduct of of the electrolysis of water. This is much more plausible, since everything else aside it is extremely improbable that Norsk would undertake a huge capital project (or attract foreign investment) to produce something which had no known commercial application and was therefore unsellable.


 * The story about Rjukan being a "heavy water plant" is almost certainly the legacy of the many poorly researched and sensationalist accounts of partisan operations undertaken against the facility during World War II. The fact that there wasn't nearly enough heavy water at Rjukan to produce enough fissile material for an atomic weapon -even if Germany was trying to build one, which it wasn't- gets downplayed because it doesn't make for nearly as good a story. Lexington50 (talk) 06:17, 21 March 2013 (UTC)

Clarification regarding pH 14
Partially refined heavy water recovered from the wreck of the M/F Hydro contained potassium hydroxide. Hydroxide was used in the electrolytic refinement process to increase conductivity. &mdash;Ryanrs 05:40, 9 March 2006 (UTC)

Yep. The actual pH (pD) of pure heavy water is 7.41. This has been fixed. Sbharris 19:49, 1 May 2006 (UTC)

Trinity link
The "Trinity" link in the neutron moderator section leads to the page on the religious Trinity; this would be improved if it led instead to the "Trinity (disambiguation)" page, or better yet, to the "Trinity test" page. Dragonbones 08:56, 17 May 2006 (UTC)
 * Fixed. But be bold and feel free to fix such stuff yourself, when you find it! I merely replaced Trinity with Trinity test, exactly as you suggested.Sbharris 15:32, 17 May 2006 (UTC)

Heavy water is not produced by a "reactor"
An Associated Press story today is mis-headlined "Iran Opens Nuclear Reactor", whereas the subject of the article is a heavy-water production plant. This error was propagated into the "Iran" section of the article, which I have since corrected to "heavy water production facility" and not "reactor." Mike Doughney 02:23, 27 August 2006 (UTC)


 * Such blatent scientific errors have become disgustingly frequent by the Associated Press during the decade of 2001 - 2010, if not ever earlier than that. The only thing that they have to say for themselves is that the problem is even worse amoung foreign news organizations such as Reuters, and that the problem with such errors is an order of magnitude worse among other overseas news organizations. When you see such errors in AP articles, you are welcome to write them e-mail about them at info@ap.org, but I will tell you now that they Never acknowledge any such corrections (not even with a slight tip of their hats), and they rarely do anything about them, either. Also, the e-mail addresses of their reporters, editors, and so forth are simply not available. This is quite a bit different from a lot of American newspapers, such as the one in San Diego, where they publish a reporter's e-mail address with with his/her byline. I was rather surprised when I questioned something about an article in the San Diego newspaper, and I got a reply about it later on that afternoon. I had thought that the best that I could hope for was something several days to a week later. Hence, such organizations as the Associated Press are going around with their heads buried in the sand as far as corrections are concerned.98.67.163.173 (talk) 05:04, 19 January 2010 (UTC)


 * Complicating the matter in the case above is the fact that chemical engineers call certain units in chemical plants "reactors", because those are where chemical reactions take place. Thus, tossing around words like "reactor" ad litum is bad when at least on its first appearance, "nuclear reactor" ought to be stated.98.67.163.173 (talk) 05:04, 19 January 2010 (UTC)

Accidental ingestion section
I see the Point Lepreau incident (the "Incidents of accidental ingestion" section of the article) was removed without comment and then quickly revived. Does that section really belong here? The section states "this was not really an incident of heavy water poisoning" (i.e., in a chemical sense), so the section isn't really appropriate if its point is to illustrate the toxicity of heavy water. OTOH, the section also talks about how little heavy water each person consumed (well below the expected level for an observable effect), so it's also not really appropriate if its point is the relative nontoxicity of heavy water. So just what is the point here? "Someone did something that isn't expected to be dangerous and nothing really bad happened" doesn't seem worthy of being in an encyclopedia. DMacks 21:46, 7 September 2006 (UTC)


 * I wasn't involved in this section's creation, deletion or restoration. I PRESUMED that it was left in, as a "mythbuster" section to counter what might have been reported as heavy water poisoning at the time, and which might even now turn up, in a Google search looking for the topic. Sometimes you have to mention stuff which a lot of people believe or was inaccurately reported, even if it's silly. I'll see if I can highlight that in the heading or intro sentence. S  B Harris 22:10, 7 September 2006 (UTC)


 * Looks good. Thanks! DMacks 22:50, 7 September 2006 (UTC)

Hygroscopic
I understand that heavy water is (unexpectedly) hygroscopic, which can of course affect its purity in lab settings. This was a problem in some attempts to duplicate the cold fusion experiments. --Wfaxon 14:01, 20 October 2006 (UTC)


 * Is it really unexpected or substantially more hygroscopic than light water? To a quick approximation, water molecules always continually exchange between vapor and liquid, but here that causes a visible effect because it leads to scrambling of the initial vastly different isotopic compositions. DMacks 15:52, 20 October 2006 (UTC)


 * Please Google ("heavy water"+hygroscopic) for many references confirming that D2O is hygroscopic. E.g.,


 * http://physchem.ox.ac.uk/msds/DE/deuterium_oxide.html


 * http://links.jstor.org/sici?sici=0080-4630(19370401)159%3A898%3C410%3ATNIASO%3E2.0.CO%3B2-Z


 * By-the-by, just because some fact is unexpected to me doesn't mean it would be unexpected to someone more knowledgable. I just thought this fact should be mentioned in this article. --Wfaxon 08:52, 21 October 2006 (UTC)


 * Right. I'm certainly not denying that it's hygroscopic in practice...I've had to throw away a lot of heavy water that has gotten contaminated. DMacks 07:28, 23 October 2006 (UTC)


 * Yes this label of hygroscopic is interesting but confusing. As stated by Dmacks, it is simply a fact of exhange of "water" molecules where your precious heavy water liquid is attempting to come into isotopic equilibrium with the light water vapour in the air. By this definition, light water could also come with a label "hygroscopic" since it is constantly exchanging with air. The only difference is that you would have great difficulty in seeing this. Perrier should come with a "warning: hygroscopic" label.Judge Nutmeg 04:56, 28 January 2007 (UTC)


 * Agreed. I don't think there's anything special about how well D2O sucks water out of the air compared with normal water. It's just that for D2O, you notice it. S  B Harris 06:28, 28 January 2007 (UTC)


 * "I've had to throw away a lot of heavy water that has gotten contaminated." "It's just that for D2O, you notice it."  The fact has been noted by several researchers and is included in data tables for D20.  I believe this fact is sufficiently important to include in this article.  How about this:


 * Researchers have noted that heavy water is very hygroscopic, that is, it absorbs regular (light) water from the atmosphere, being reduced in purity thereby. But the literature is unclear as to whether this is true absorption of atmospheric water or just normal molecular exchange of the liquid (heavy) water with atmospheric (light) water.


 * You can perhaps make that a little less awkward, but you get the point. (Hmmm, there is no Wikipedia entry for molecular exchange...)  --Wfaxon 08:22, 17 February 2007 (UTC)


 * The heat of vaporization is different - slightly higher - from H2O, so it truly would have a very mild net hygroscopic effect if added to a closed, 100% humid system of exactly equal temperature. When the gas inside this closed system were later evaluated, the total amount of oxygen atoms (regardless of what they ended up stuck to) in the gas portion as vapor would be lower, and the total amount of oxygen atoms in the liquid portion would be higher, due to that difference. Basically, the D2O cools more evaporating than the H2O will heat condensing... Zaphraud 02:57, 26 July 2007 (UTC)


 * You writers in this section need a different word besides "hygroscopic". Hydroscopic means that the substance absorbs water, but to state that heavy water is "hygroscopic" is rather like stating that fire is flammable; acids are acrid; and ice is icy.98.67.163.173 (talk) 05:13, 19 January 2010 (UTC)

Bombing of the Norsk Hydro
In a PBS documentary about the Norsk Hydro Plant and the attempts to sabotage it, it was stated that, on 16 November 1943, Allied forces did drop over 400 bombs, but failed to do enough damage to the heavy water production facilities to halt production. Many other buildings were damaged or destroyed, but heavy water production continued. Has anyone else seen this documentary?

Merge/split
It seems to me that the differences in names for the entries for heavy water and tritiated water is a little "off". If these individual articles are to exist, they probably ought to redirect to the chemical names of deuterium and tritium oxide. It also seems like clearer attention should be paid to consistency. This article says both that heavy water is a loose term (implying that it's okay to use for any water molecule with neutron bearing hydrogen isotope{s}) and then one paragraph later saying that "it should not be confused with tritiated water." Finally, it seems like all of the molecular isotopes should be covered somewhere, and probably in the same place. In support of a central merge is the ability to clearly compare properties and avoid the need to repeat the same text everywhere about what causes the difference in properties. --Belg4mit 03:11, 17 May 2007 (UTC)

A random spin-off thought about this article
Does D218O exist? If so, what are its properties? 82.36.26.70 13:03, 21 August 2007 (UTC)
 * See Doubly-labeled water. - BANG  !  00:08, 22 August 2007 (UTC)

More on toxicity
The article states a number of thing that is news to me such as
 * Experiments in mice, rats, and dogs[3] have shown that a degree of 25% deuteration causes (sometimes irreversible) sterility, because neither gametes nor zygotes can develop. High concentrations of heavy water (90%) rapidly kills fish, tadpoles, flatworms, and drosophila. Mammals such as rats given heavy water to drink die after a week, at a time when their body water approaches about 50% deuteration. The mode of death appears to be the same as that in cytotoxic poisoning (such as chemotherapy) or in acute radiation syndrome (though deuterium is not radioactive), and is due to deuterium's action in generally inhibiting cell division. Deuterium oxide is used to enhance boron neutron capture therapy.[3] It is more toxic to malignant cells than normal cells but the concentrations needed are too high for regular use.[3] As in chemotherapy, deuterium-poisoned mammals die of a failure of bone marrow (bleeding and infection) and intestinal-barrier functions (diarrhea and fluid loss).

This is supposedly backed up by a reference to this article which turns out to be an abstract that does not make any of the above clear. Could anyone have a closer look at this? --21:06, 30 October 2007 (UTC)
 * I've read the whole article and all or most of this info is in there. And it's all true :). Feel free to dispute any given bit after finding the article yourself, reading it, and so on. S  B Harris 21:08, 30 October 2007 (UTC)
 * I stated it was news to me and I admit I was rather surprised, however I have the professional humility not to dismiss what I do not know. I have no reason to disbelieve you and will accept you vouching for its factuality. Still, I would like to have read the article in its entirety but have no longer access to research libraries. Nevertheless the abstract alone does not work well as a convincing reference. Is there any good peer reviewed freely available article on the net that can be used instead? Incidentally this seems like a good example where be bold would not be useful, I prefer discussions rather than deletions.--20:02, 31 October 2007 (UTC) —Preceding unsigned comment added by 85.164.191.237 (talk)
 * I don't know of any. Here's an old article where it notes that death occurs in mice spontaneously rather quickly when given %75 deuterated water, but you're going to have to tell me just what it is you don't believe about this stuff which isn't at least hinted at in the abstact you've got. S  B Harris 23:40, 11 November 2007 (UTC)

Expense in section Heavy-oxygen water
Why is it more expensive to make 17O than 18O? "Even more expensively, water is available in which the oxygen is 17O."

Webhat (talk) 02:23, 21 January 2008 (UTC)


 * Probably because O-18 is five to six times more abundant that O-17, according to isotopes of oxygen. --Itub (talk) 13:07, 21 January 2008 (UTC)
 * Exactly so. S  B Harris 20:34, 21 January 2008 (UTC)

Norsk Hydro floating barrels
I recently saw the NOVA program on recovering a barrel. The barrel recovered in 2004 had a D2O concentration of 1.1% plus or minus 0.2%. Lower numbered barrels had a higher concentration (there wasn't any elaboration on what the concentration was in the program) but were only half full and would have floated. The full transcript of the program can be read at http://www.pbs.org/wgbh/nova/transcripts/3216_hydro.html. The passage in question is "The manifest shows that the low-numbered barrels which contained the high concentration heavy water were little more than half full. That explains why some of them floated." --Shagie (talk) 04:20, 30 April 2008 (UTC)

Medical Uses for Heavy Water
The USPTO issued patent 5223269 for use of heavy water to treat high blood pressure. This probably explains the earlier reported incidents of dizziness upon ingestion. Easycrypto (talk) 21:21, 2 July 2008 (UTC)Easycrypto

Physical Properties
I got here looking for more information on the color (or lack thereof) of D2O as seen through long column lengths. In particular, verification that the change in mass vs H2O shifts the harmonics for vibrational transitions out of the range which give H2O it's blue tint and down into the IR range, thereby rendering D2O colorless. Reference Braun, C.L.; Smirnov, S.N., J. Chem. Edu., 70 (1993) 612 If so, please consider adding additional information to Physical properties obvious by inspection section of page. Stressedprotons (talk) 12:03, 6 September 2008 (UTC)

D2O ice used as a gimmick
I have just seen an episode of a cooking show on tv - New Scandinavian Cooking. The presenter used ice made of D2O in a cocktail drink. The gimmick being that it sank to the bottom of the drink which was mostly vodka and aquavit. The implication of this use is that (at least in Norway) D2O is relatively easy to obtain. Roger (talk) 08:12, 10 October 2008 (UTC)


 * This demo is mentioned in the article. D2O is easy to obtain. And the demo works even in straight light water with no alcohol. S  B Harris 10:43, 10 October 2008 (UTC)

Weight of heavy water
How much heavier would the "proverbial milk bottle" of heavy water be than that of ordinary water? (And ditritium oxide for that matter.) Jackiespeel (talk) 18:19, 23 February 2009 (UTC)
 * What is the volume of the bottle? What is the density of "normal" water? Calculate how much that volume of that density liquid weighs. Repeat for heavy water. DMacks (talk) 18:22, 23 February 2009 (UTC)


 * The "proverbial one pint" - or one litre if more convenient. A note on the page (A container of D2O weighs x% more than the same of water) (and likewise for any other variations of ordinary water that people care to add).


 * A reference to the WW II milk bottle of heavy water in the fridge. Jackiespeel (talk) 17:24, 25 February 2009 (UTC)


 * It weighs 10.6% more than an equal volume of standard water. The bottle, of course, is the same. So you figure it out. S  B Harris 02:41, 6 August 2009 (UTC)

Hogan's Heroes
Would anyone mind if I added a reference to the Hogan's Heroes episode "Go Light on the Heavy Water"? Just saw it, and afterwards navigated to this page to learn more. In the episode they say that the heavy water came from Norway, and Colonel Klink (thinking it is spa water which will grow hair) drinks it.

Thanks, Stuart H. Alden (talk) 02:30, 6 August 2009 (UTC)


 * Not relevant here. Check the Hogan's Heroes page - more relevant there. Vsmith (talk) 02:33, 6 August 2009 (UTC)
 * No, please. Anything but Hogan's Heros. We've managed to get rid of all the silly cultural pop culture references to heavy water in this serious science article. But there's a long list of them in previous versions, where you could put the Hogan's Heros. As per WP:TRIVIA, separate cultural reference articles are actually encouraged as stand-alone lists. Where they don't ruin an article like this one, except with a one-line link for somebody who really wants to see every book and film and cartoon and TV show and song that has ever mentioned the stuff, ever. S  B Harris 02:39, 6 August 2009 (UTC)


 * Sounds good, thanks. Stuart H. Alden (talk) 12:39, 6 August 2009 (UTC)

Production
In the section on production the following is stated:

"The HDO may be separated from regular water by distillation or electrolysis and also by various chemical exchange processes, all of which exploit a kinetic isotope effect."

But - since O-18 is relatively more abundant than D wouldn't the stated processes give you a lot of H2O-18 instead of HDO ? 72.28.181.101 (talk) 20:50, 28 September 2009 (UTC)
 * Except for the simple distillation approach, the other routes do not literally separate "light water from heavy water" directly. The result of all these other routes is really to separate the H from the D not as part of a water molecule and then reform the water itself. So there may be HD18O but O-18 would not be especially enriched. Simple distillation, it's an interesting issue! HD16O is lighter (and vapor less dense) than HH18O (I don't know the latter's boiling point). It would sure seem that if you're boiling off HHO, you're enriching in both of those "heavy" forms, and in the O-18 one more than the D one (per natural-abundances you note). DMacks (talk) 02:58, 29 September 2009 (UTC)

Copyedit
I made a copyedit which was reverted. I restored my change as I thought it was an improvement. I mainly focused on standardizing on MoS compliant spelling and formatting, and on removing unreferenced material. What do others think? --John (talk) 21:18, 28 October 2009 (UTC)
 * I have some sympathy with the person who reverted your copyedit. Your edit mixes straightforward changes such as capitalization, which I don't think anyone will object to, with deletion of entire sentences, at least one of which for no apparent reason. I think in general it's better to split such different kinds changes into separate edits, and give detailed reasons when deleting information. --Itub (talk) 13:42, 29 October 2009 (UTC)
 * I deleted the sentence "Since this war, heavy water has played a part in a number of reactor designs, both in designs for power and for nuclear weapon-making." as I thought it was too detailed for the lead. On reflection, I have restored it. I also deleted some stuff about the medical effects which was highly detailed but tagged as needing a citation. This is what a copyedit is, to me, as well as fixing errors in capitalization and spelling. On which note, is the article using British spellings? I assumed so, but I think there are instances of both variants. --John (talk) 00:38, 30 October 2009 (UTC)
 * The Wikipedia organization has been established and operated as a non-profit corporation under the Federal laws of the United States of America, and furthermore, it is operated by Internet servers located in the United States, and furthermore, it operates under the copyright laws of the United States. So, whose spellings should be used here? (and that is a rhetorical question, too). It someone wants to use British spellings, etc., let them establish their own "Britipedia" and use that one.98.67.163.173 (talk) 05:35, 19 January 2010 (UTC)

Heavy Water vs. Light Water reactors
This article had said that heavy water was essential in nuclear reactors, and then it immediately contradicted itself by telling about light-water reactors, before I corrected the mistake. Here is a probable source of the confusion. Among reactors that use liquids for their moderator and coolant, ones that are made with natural uranium metal (about 0.7% uranium-235) will not achieve a critical reaction if light water is used. This is because the normal hydrogen ( H-1 ) in light water will absorb too many of the free neutrons that are emitted by fissioning U-235, and this damps out any chain reactions. What happens is that a significant number of the H-1 nuclei will absorb one neutron apiece and become deuterium, but not enough to make any gross difference in the nuclear properties of the water. There are two roads to overcoming this problem: A. Use heavy water instead of light water in the reactor, retaining the natural uranium fuel, because deuterium does not absorb neutrons very much at all. Then, the chain reaction is sustained, and the chain reaction becomes a critical reaction. B. Use somewhat-enriched uranium, which has been processed to the point that it contains about 3.5% U-235. (Note that weapons-grade U-235 has been enriched a lot more - to the 90% level or beyond.) Large amounts of this somewhat enriched uranium generate enough excess neutrons that the chain reaction is sustained. This is in spite of the fact that some of the neutrons are absorbed by H-1 nuclei.

By far, most nuclear reactors that have been made and used in the United States have been light-water reactors, and especially since modestly-enriched uranium has been available from the three large gaseous-diffusion plants that the United States used to have, such as the K-25 plant near Oak Ridge, Tennessee. However, some other countries have made common use of reactors that are cooled and moderated by heavy water. One example of this is in the Canadian-made "CANDU reactors" that have been widely used both there and as exports to other countries. The acronym "CANDU" stands for CANadian Deuterium Uranium reactor.

Other kinds of moderation and cooling of nuclear reactors have either been experimented with or used commercially. Some of these use graphite for the moderator, and then the coolant can be either light water, heavy water, or carbon dioxide. For the light-water cooled ones, the absorbtion of neutrons is overcome by using somewhat-enriched uranium. The other two types do not have this problem (and hence can use natural uranium metal, if they are large enough) because neither heavy water not carbon dioxide absorbs neutrons strongly.

Also, some nuclear reactors, mostly experimental ones, have used other coolants and moderators. For example, liquid sodium has been experimented with as a coolant, combined with I don't know as the moderator. The old U.S. Navy nuclear submarine USS "Seawolf", completed in the 1950s, used liquid sodium as its coolant. However, that reactor turned out to be unsuitable, and several years later, it was replaced with a conventional light-water reactor. That old USS "Seawolf" has long ago gone to the nuclear submarine's scrap heap in Washington State. A newer, much more modern submarine, USS Seawolf (SSN-21), was commissioned in about 1996, it remains in service, and it always has had a conventional light-water reactor.

Using liquid sodium for the reactor coolant has some serious drawbacks. First of all, if any amount of sodium ever leaks out of it and comes into contact with water, there is a spectacularly violent chemical reaction. Also, sodium liquifies somewhere between 500 and 600 degrees Farenheit, and if the sodium ever cools down below that point, it solidifies in every pipe, every valve, and every pump in the system, and then the reactor operators have hell to pay to get the reactor in operation once again. On the other hand, liquid-cooled or gas-cooled rectors can be SCRAMed (shut down) at almost any time, allowed to cool down to room temperature, and then started back up again with little trouble.98.67.163.173 (talk) 07:01, 19 January 2010 (UTC)

Wait, sodium melts at 98C (200F), it'll melt in boiling water. In addition, from memory, a eutectic mix of sodium and potassium solidifies well below 0C. The problem, as you say, lies more in the reaction with water. 118.208.105.69 (talk) 01:55, 22 January 2010 (UTC)
 * See table in Liquid metal cooled reactor. --JWB (talk) 04:51, 22 January 2010 (UTC)

History - non-fission applications
The Norwegian heavy water sabotage event was aimed against the Norsk Hydro heavy water production that began in 1934. Neither this article nor the Norwegian heavy water sabotage article state why Norsk Hydro was producing heavy water. It wasn't for fission experiments. Could a knowledgeable editor add this information to the articles? Comet Tuttle (talk) 00:15, 17 April 2010 (UTC)

Pure D2O radioactive? I think this part needs fixing.

 * "Pure heavy water is slightly radioactive from minute traces of contaminating natural tritium present in it, but the same is true of ordinary water as well."

Pure heavy water, by definition, should be pure, and not contain any trace amounts of anything else than deuterium and oxygen, no? (I'm ignoring WP:BOLD since I'm not completely sure.) -- Aeluwas (talk) 12:46, 6 June 2010 (UTC)


 * If that is the explanation, then it is not pure. I think what was intended is: "Given the practically achievable level of purity, so called "pure" heavy water is slightly radioactive from..." Roger (talk) 14:32, 7 June 2010 (UTC)

Cost of D2O
How much does D2O cost? Is it readily obtainable? Stonemason89 (talk) 00:46, 26 August 2010 (UTC)

It's relatively inexpensive. Most suppliers call it "deuterium oxide". --Rifleman 82 (talk) 01:08, 26 August 2010 (UTC)


 * I looked at a few US based chemical suppliers websites - prices range from US$1.00 - 2.00 per ml depending on the quantity and packaging. (E-Bay offerings are mostly overpriced.) Roger (talk) 11:15, 28 August 2010 (UTC)

Other heavy hydrogen compounds
Why is heavy water the only heavy hydrogen compound ever mentioned. Ive never heard any mention of things like heavy methane or heavy ammonia. — Preceding unsigned comment added by Jimmy saville (talk • contribs) 14:57, 26 October 2011 (UTC)
 * It's a historical term that caught on and is still in use. The newer compounds are made and used-- for example CDCl3 is used as an MRI solvent, but the preferred term now is "deuterated," so this is deuterated chloroform, not "heavy chloroform." There are entire catalogs available of deuterated solvents and other deuterated compounds. Incidently, those catalogs don't sell "heavy water" but rather "deuterium oxide." S  B Harris 15:46, 26 October 2011 (UTC)

Requirement for heavy water in plutonium production
"Had the German nuclear program followed similar lines of research as the US Manhattan Project, the heavy water would have been crucial to obtaining plutonium from a nuclear reactor" The Manhattan Project used graphite moderated light-water cooled reactors for plutonium production. AFAIK heavy water was useful for research purposes only. — Preceding unsigned comment added by 203.167.252.122 (talk) 04:00, 13 January 2012 (UTC)

Graphene question
There have been recent reports that graphene is effectively impervious to all other gasses and vapours, but lets water through freely - so much so that a demonstration even used it to concentrate vodka further, just by leaving a bottle of vodka capped with graphene in the open for a while. This made me wonder, have there been any experiments to see if it has the same behaviour with heavy water, semi-heavy water or tritiated water? If there is even a small difference in graphene's permeability to those and to ordinary water it could have significant practical implications for producing heavy water, and this speculation of mine would firm up enough to be mentioned in the article proper. PMLawrence (talk) 07:40, 28 February 2012 (UTC)
 * Read an article on this, but I didn't see how this would concentrate the vodka. The article doesn't say anything about graphene being directionally permeable. JohndanR (talk) 23:47, 10 July 2016 (UTC)

Plainer English Please
This article needs to be rewritten on a more elemental level. As it is now, one has to have mastered high school or college chemistry in order to understand it. Perhaps a synopsis section, written on the scientific literacy level of a newspaper article, would be appropriate. Thanks.


 * We can add a sentence or two in the very intro. But it's an inherrently complex topic. If you don't understand the concept of isotope you have to learn it first, and the intro of this article is not the place to explain all that. If we did, somebody else would complain that that was better done in the isotope article, instead of cluttering up this one! You see the problem. In newspapers there's no way to hyperlink to concepts you need to understand first, so you can't do that. But on Wikipedia, we can. That's part of the genius of computer hypertext media. S  B Harris 04:57, 10 December 2012 (UTC)

The Water in Human Body
I changed in Because it would take a very large amount of heavy water to replace 25% to 50% of a human being's body water (which in turn is 70-75% of body weight [27]) with heavy water, accidental or intentional poisoning with heavy water is unlikely to the point of practical disregard., that water is 70-75% of body weight [27]. There are relaible sources. For 60-70% water of body weight there are not relaible sources in modern science. --Analiticus (talk) 12:54, 25 April 2013 (UTC)
 * Wrong. 73% is at the very outer limit for adults. Here is a very large sample of adults of all ages and both sexes and the figures are 48 ±6% for females and 58 ±8% for males. See table 1. . Your source is online here . It finds 55% which is embarrassing for you (see table 2 and do the division). Your number is from another source this one quotes internally (Wang, 1992 ) that actually says 60% (and gives yet another source). So your source makes an internal quotation error and you followed it. S  B Harris 15:29, 25 April 2013 (UTC)

Dear SBHarris, I agreed for 65-70%. Thank you.--Analiticus (talk) 19:30, 25 April 2013 (UTC)


 * You might have agreed for it, but I didn't. You can't find a reliable source for 65-70% for adult humans. It goes up to 66% in men (one standard deviation) and is less in women. S  B Harris 01:23, 29 May 2013 (UTC)

Circadian oscillations
In "Effect on biological systems" : "Heavy water is the only known chemical substance that affects the period of circadian oscillations, consistently increasing the length of each cycle. The effect is seen in unicellular organisms, green plants, isopods, insects, birds, mice, and hamsters. The mechanism is unknown.[15]"

Is this line still relevant? The citation is from 1973. Plus if you click on the link, you are brought here

Which then says "HighWire Press-hosted articles citing this article" and leads to this article which states that Lithium can increase the circadian period length in animals.

Furthermore is the mechanism still unknown?

129.49.21.25 (talk) 05:19, 26 July 2013 (UTC)Victoria

USSR 1934
Is there any source for the following sentence? "Production was first started in 1934" --Fmrauch (talk) 17:21, 1 January 2014 (UTC)

"In 1934 the Department of Physical Chemistry under Professor DHTI OI Brodsky first time in science received a heavy isotope of hydrogen (heavy water), which gained it fame Institute of powerful scientific establishment of the country."  (the "O" is short for "Oleksandr")

"The first Soviet conference on nuclear physics was held in Leningrad in 1933. It gave a strong impetus to further investigations. A year later, Alexander Brodsky produced the first heavy water in the USSR." 

"140 1935 ACTA PHYSICOCHIMICA URSS 2 (5): 603-610 Brodsky AE; Scarre OC Exchange reactions of hydrogen with deuterium I Exchange in carboxyls of succinic acid and in hydroxyls of hydroquinone"

"Fractionating columns for 18O has also been constructed by Brodsky and co. and later by Baertschi and Kuhn." (18O being oxygen-18)

"In early 1931 Sinelnikov returned from Cambridge to organize a nuclear group in Kharkov at the Ukrainian Physico-Technical Institute (UkFTI), which had been set up by a group of scientists from the Leningrad Physico-Technical Institute (LFTI) in 1928." 

"BRODSKY Alexander Iljich (1895-1969), fizikohimik, academician AN of Ukraine (1939), corresponding member AN the USSR (1943), the Hero Socialist Transactionses (1969). The main{basic} transactionses on electrochemistry, chemistry and an isotope separation, the theory of a chemical bond. Under Brodsky guiding for the first time in the USSR installation on obtaining a heavy water (1934) is built." 

The Russian Wikipedia has a biography of Brodsky but it doesn't mention heavy water. The Russian Wikipedia page about heavy water doesn't mention Brodsky or the 1934 date, nor does the one source it cites.

Searching for Бродский Александр Ильич Тяжёлая вода тяжелой воды, I found numerous Web pages that support the statement. Which, if any, are reliable, I don't know.

&mdash; rybec 00:30, 2 January 2014 (UTC)
 * http://warheroes.ru/hero/hero.asp?Hero_id=12882
 * http://biografija.ru/biography/brodskij-aleksandr-ilich.htm
 * http://megabook.ru/article/БРОДСКИЙ%20Александр%20Ильич
 * http://pusk.by/bbe/13382
 * http://tolkslovar.ru/b6836.html
 * http://drpsklibr.at.ua/news/brodskij_aleksandr_ilich_115_let_so_dnja_rozhdenija/2010-06-17-141
 * http://www.bochvar.ru/photo/photoevents/photo_exib_fme/vistavka_10/
 * http://globalpedia.ru/people.php?id=2691&category=278
 * http://www.r-g-d.org/B/brodsky.htm

Effect on biological systems
I am physicist and I published the results of heavy water and biological systems. The sources are reliable. I hope that I will be useful. Mbreht--Mbreht (talk) 10:32, 25 August 2012 (UTC)


 * For this text have not reliable sources. It can be removed. Which is "Institute for the Biology of Ageing, located in Moscow"? "It has been proposed that low doses of heavy water can slow the aging process by helping the body resist oxidative damage via the kinetic isotope effect[clarification needed].[27] A team at the Institute for the Biology of Ageing, located in Moscow, conducted an experiment to determine the effect of heavy water on longevity using fruit flies and found that while large amounts were deadly, smaller quantities increased lifespans by up to 30%.[28][clarification needed]"--Analiticus (talk) 19:22, 10 April 2014 (UTC)


 * Pending discussion, I have reverted your edit-summary-less content removal. - DVdm (talk) 19:36, 10 April 2014 (UTC)


 * Dear DVdm the text which I canceled is without reliable sources with impact factor. There is additional information in Deuterium-depleted water:
 * https://en.wikipedia.org/wiki/Deuterium-depleted_water --Analiticus (talk) 20:22, 10 April 2014 (UTC)


 * To be fair he's probably right, that paragraph amounts to a health claim, which puts it under WP:MEDRS. You're supposed to have more than just primary references to back up something like that Project Osprey (talk) 20:39, 10 April 2014 (UTC)


 * Repaired my heading mistake and fixed indentation, hoping you don't mind.
 * Ok, I can live with that. Cheers - DVdm (talk) 20:45, 10 April 2014 (UTC)


 * This is link to Institute for the Biology of Ageing: http://moikrug.ru/circles/687351892/

This Institute has not site, devices for research of heavy water, these three people have not publications in jornals with impact factor. --Analiticus (talk) 04:50, 11 April 2014 (UTC)
 * I removed again this text. From the position of science this text is uncorrect - Institute for the Biology of Ageing without real scientific research and publications with impact factor of the members, research without proofs for influnce of heavy water om longevity, the place of similar type of this text is hear: https://en.wikipedia.org/wiki/Deuterium-depleted_water

This text needs more than just primary references. The primary references are not relaible. https://en.wikipedia.org/wiki/Wikipedia:MEDRS --Analiticus (talk) 05:16, 11 April 2014 (UTC)

Nonsensical statement
"

On Earth, deuterated water, HDO, occurs naturally in regular water at a proportion of about 1 molecule in 3200. This means that 1 in 6400 hydrogen atoms is deuterium, which is 1 part in 3200 by weight (hydrogen weight)."

The last part of this sentence is nonsense. About 1 in 6400 hydrogen atoms is deuterium, which results in about 1 in 3200 water molecules containing a deuterium atom,   because each water molecule contains 2 hydrogen ( or deuterium ) atoms. It has nothing to do with "weight" or "hydrogen weight".Lathamibird (talk) 01:40, 30 March 2015 (UTC)

The weight of heavy water
To make it easier to visualize - how much would 'the proverbial bottle of milk' (or 500 millilitres) full of the different types of water weigh compared to 'a bottle/500 ml of ordinary H2O'? Jackiespeel (talk) 15:09, 7 August 2015 (UTC)


 * The specific gravity of milk is ~3% more than normal water. The specific gravity of D2O is ~10% more than normal water. Hope that helps. --Energy4All (talk) 16:26, 6 November 2015 (UTC)

Semiheavy water
What is the point of this subsection - is it trying to explain hydrogen ion dissassociation in water? Also, I have heard the term "down-graded heavy water", but never "semiheavy water". Does anyone use this term? Energy4All (talk) 16:21, 6 November 2015 (UTC)

2H(2)O
When I Google 'heavy water' I see an excerpt from the Wiki article that says 2H(2)O, instead of superscripting the first 2 or giving D(2)O. Is this from this article or does Google do its own thing? --Richardson mcphillips (talk) 16:46, 23 December 2015 (UTC)


 * Yes, it's just Google ignoring superscripts.    D b f i r s   17:23, 23 December 2015 (UTC)

ok, thanks. I guess Google is so close to achieving self-awareness that it would be dangerous to try to correct it. --Richardson mcphillips (talk) 19:55, 17 January 2016 (UTC)

Assessment comment
Substituted at 17:31, 29 April 2016 (UTC)

Name
Is there a name for the protium-based water? The article seems to call it "normal water", but I would imagine there is a technically precise term in common use among physicists, such as diprotium hydroxide or similar? It seems like a precise term would be more appropriate for this article. — Preceding unsigned comment added by 75.139.254.117 (talk) 04:57, 28 December 2016 (UTC)
 * "Light water", which is mentioned in the article, especially when specifically discussing it as a comparison. "Protium oxide" and similar I imagine are reasonable (by comparison chemical catalogs list "deuterium oxide" for specifically the D2O form). See also for example Light-water reactor and Light Water Reactor Sustainability Program. DMacks (talk) 22:00, 1 January 2017 (UTC)

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Sweet taste
I just tasted heavy water (Sigma Aldrich, 151882, Deuterium oxide, Purity 99.9% Atom % D) and it is definitely sweet. This is commonly reported , however I cannot find any official source. Maybe someone can help? -Eio (talk) 18:10, 10 January 2018 (UTC)

JCPOA : Iran's energetic and medical nuclear program
For at least one year the USA bought Iran's surplus heavy water. That's worth publishing so I did. User:GrapefruitSculpin cut it. I don't want to get into an edition war so I won't undo his/her action but it should be published as it had and was a meaningful political message by political actors. The reflex to remove what one's doesn't seem fit even if WP rules are respected (namely good sources, MIT and Washington times in this case) is a nefarious habit that doesn't help to get people involved in the wikipedia project. If you rephase my broken English, it's ok but don't erase facts.

definition of heavy water
This article is wildly inconsistent in what is meant by the term "heavy water". The very first sentence uses two definitions: D_2O, which is water consisting of one oxygen atom and two deuterium atoms, and "a form of water that contains a larger than normal amount of the hydrogen isotope deuterium", which would include water molecules with one deuterium atom and one protium atom, as well as a mixture of these types. Later in the article other forms of water that contain no deuterium at all (water containing tritium, or isotopes other than O16 of oxygen) are discussed. The article should pick one definition of "heavy water" and stick to it. Either this needs to be split into various articles on these various meanings of "heavy water", or the lede should be revised to be consistent with the content of the article. defining heavy water as any water that contains a larger than normal number of atoms with higher than usual atomic weights.Andylatto (talk) 19:25, 4 February 2020 (UTC)

Explanation - "naturally 5 grams heavy water in human body"
"The human body naturally contains deuterium equivalent to about five grams of heavy water, which is harmless." What does this mean for the body ? Is the body collecting these lot (5 grams), to a health lot ? What if less or ´too less´ in the body ? --Visionhelp (talk) 18:06, 14 February 2020 (UTC)

Inconsistent meaning of the term "heavy water" across the article
The first sentence says that heavy water is water that contains higher than normal amounts of deuterium atoms in its molecules, sugesting that heavy water is not only deuterium oxide D2O, but also protium deuterium oxide HDO, and mixtures of protium oxide H2O, protium deuterium oxide HDO and deuterium oxide D2O as well. But the same sentence begins with "Heavy water (deuterium oxide, 2H2O, D2O)", and the header of the second column of the table named "Physical properties of isotopologues of water" is "D2O (Heavy water)", and the whole "Physical properties" section and the whole table named "Heavy water" at the beginning of the article, as well as the IUPAC name of heavy water, sugest that heavy water is deuterium oxide D2O, not protium deuterium oxide HDO, and not mixtures of protium oxide H2O, protium deuterium oxide HDO and deuterium oxide D2O. The article should stick to one meaning of the term "heavy water", not confusing readers by jumping back and forth between several different meanings. Bernardirfan (talk) 01:50, 28 July 2020 (UTC)
 * I adjusted the intro to be self-consistent about being D2O. DMacks (talk) 03:45, 29 July 2020 (UTC)

Why contradict in explanation?
the explanation section includes the following sentences:

“A molecule of heavy water has two deuterium atoms in place of the two protium atoms of ordinary "light" water. Actually, the term heavy water as defined by the IUPAC Gold Book can also refer to water in which a higher than usual proportion of hydrogen atoms are deuterium rather than protium.”

The self-contradiction is unnecessary, and the wording should be changed to explain that the term “heavy water” has multiple used definitions. 107.127.7.41 (talk) 21:51, 13 June 2022 (UTC)


 * The "also"-word from the quote you gave saves it from being a contradiction. · · · Omnissiahs hierophant (talk) 16:22, 14 June 2022 (UTC)

It does not. The word “actually” implies that the previous sentence is incorrect. Kerg1 (talk) 05:03, 15 June 2022 (UTC)


 * I did remove the "actually"-word from the article.. before you made your comment it seems. (And I disagree, but whatever.) If you rly want to you could ofc just click [edit] yourselves... idk ;D · · · Omnissiahs hierophant (talk) 21:51, 15 June 2022 (UTC)