Talk:Zinc oxide/Archive 1

Copyvio
Rolled back contribution from IP: suspected copyvio from http://www.navbharat.co.in/clients.htm -- Tarquin 15:17, 9 Mar 2004 (UTC)

Whoops
I just noticed this line in the third paragraph, "...less opaque than lithopone, but more transparent than titanium dioxide." These two phrases, "less opaque" and "more transparent", seem to mean the same thing. Clearly one is wrong, but which one? GBMorris 01:08, 8 May 2006 (UTC)

topical pharmacology?
Anybody know why this is a sunscreen? A diaper rash indication? Any relation to Calamine?

\\Yes it is related to Calamine. The ZnO in Calamine is used to absorb the urushiol from the poison ivy.

No, ZnO does not absorb the urushiol. Calamine is a treatment for the skin eruptions caused by the allergic response to the urushiol. (The urushiol must be washed off immediately, within 5-15 minutes of exposure to the poison ivy, before it sinks into the skin and binds there. After that, only some special drugs have any chance of actually protecting you from the urushiol.)-69.87.204.36 12:49, 27 April 2007 (UTC)

Zinc Oxide is a sunscreen, commonly used in congunction with titanium oxide as they both filter out UVA and UVB light to a high degree. Commonly used in Australia with it being its own brand called Zinc Cream, primarily used on the face, unfortunately Wikipedia has no information on this topic —Preceding unsigned comment added by 59.101.156.88 (talk) 01:08, 4 February 2008 (UTC)

Zinc oxide plaster
A friend recently told me that the pink sticking plaster one can by - the fabric version of elastoplast/band-aid - is called zinc oxide plaster. Why's it added to sticking plaster, when sticking plaster isn't normally against the wound? (At least, I wouldn't want it directly on the wound, especially at ripping-off time. Ow.)

My understanding is that zinc oxide is weakly antiseptic, hence its traditional use in sticking plasters and nappy rash creams/ointments.

As a pigment, zinc oxide is used as a sunblock, that is as a completely opaque reflective layer. The white bands that cricketers sport across their noses is a fat based paste of fairly coarse zinc oxide powder. The pigmentary effect is based on its high reflectance - not its absorbance. If it was 100% absorbant of visible light it would be black. Zinc oxide (and more commonly titanium dioxide) are also used in a micronised form where the particle size is sufficiently low with respect to UV light to be opaque (reflective) to UV, but nearly transparent to visible light. These grades are used in many modern sunscreens - the slight blue-white sheen modern sunscreen lotions sometimes give is due to the slight visibility at the blue end of the spectrum. These pigmentary sunscreens have the advantage of not degrading over time due to absorbance of UV light, unlike most organic sunscreen agents which give much reduced protection within an hour of application.

Disputed tag
There are many obviously wrong facts in this article, somebody more experienced in inorganic chemistry should check it. Cacycle 16:50, 21 August 2006 (UTC)
 * Can you give some examples of obviously wrong facts, maybe I am overlooking them. --Dirk Beetstra T  C 16:52, 21 August 2006 (UTC)

Please check these: Cacycle 17:00, 21 August 2006 (UTC)
 * 1) "... is luminescent (it will change colour from white to yellow when heated, and back again when cooled down)
 * 2) "and is light sensitive"
 * 3) "Zinc peroxide, ZnO2 .½ H2O, is a white to yellow powder used in antiseptic ointments, like Calamine Lotion."
 * 4) "Because it absorbs both UVA and UVB rays of ultraviolet light,"


 * 1) Ah .. wrong term, luminescent is probably not the right term (or another property), the experiment describes thermochromism.
 * 2) See point 4 ..
 * 3) I think it is used in some ointments, indeed, Calamine is maybe a spam ..


 * "Calamine" is not a brand name, but a generic term for zinc oxide with a small amount of ferric oxide mixed in, which gives it the pink color. Hence references to calamine are NOT spam. Karlhahn 20:31, 30 September 2006 (UTC)
 * But the reference to H2O is entirely spurious as far as I can tell. You can call ZnO2 Zinc Oxide or Zinc Peroxide, but water isn't involved. Andrew Rodland 06:44, 22 November 2006 (UTC)


 * 1) If it is in a sunblock, and you apply it to your body, it should block (absorb) UVA and UVB, right?  But indeed, if it is then light sensitive (point 2)...
 * For the last two points, Sunscreen does say that zinc oxide is one of the active components. So that sounds right to me (except .. light sensitive .. hmmm).  What this article def could use, are a handful of reference needed tags or maybe even an unreferenced.  I would not call it disputed, but an eye of chemist in the field of solar cells may also be a good idea .. expert?

--Dirk Beetstra T C 17:14, 21 August 2006 (UTC)

From what I remember it does not absorb UV, but a very fine suspension simply reflects it. Cacycle 18:09, 21 August 2006 (UTC) Would also make sense .. most energy is in the UV, so if it absorbs UV, how would the solar-cel work. And, if it absorbs, it warms up, so the sunblock could have strange side-effects. I hope someone kicks in who knows more about this subject. --Dirk Beetstra T C 18:32, 21 August 2006 (UTC)


 * ZnO seems to absorb, not only scatter UV, e.g.: http://www.totalblock.com/tinted.html
 * ZnO2 is not used in calamine lotion
 * Cacycle 01:49, 23 August 2006 (UTC)

I believe zinc oxide is used in sunblock because it reflects the rays. It is one of the whitest substances known. Here's a link from Cornell — [   Mac Davis ] (talk)


 * The luminescent (phosphorescent) compound was zinc sulfide, wasn't it, and the energy is stored in F-centers? No idea if zinc oxide does the same. As Cacycle says, zinc oxide is a wide-bandgap semiconductor, sort of like TiO_2. Can't remember what the bandgap is, but it does absorb UV. Dr Zak 02:41, 1 September 2006 (UTC)

The applications list is all over the place. My experience is with ZnO as a semiconductor material. THere should probably be an optical-electronic property related section and a chemical property related section. Anyway, ZnO has a band gap a room temperature of about 3.2, meaning that it absorbs very strongly for photons of more than 3.2 eV energy, wich is about 387 nm wavelength. I would not expect that absorbing (instead of reflecting) UV would cause a heating sensation because, 1) your skin would regularly (without sun protection) absorb the UV and 2) less than 10% of the solar radiation energy is in the UV. ZnO powder looks so white because it has a high index of refraction. It's about n=2 in the visible range, increases a bit going from blue to violet. This is just my own memory, but I checked it here: http://www.luxpop.com/cgi-bin/calc_v1.0.0.cgi Which gives 2-2.2, dependant on wavelength. ZnO has many similarities with TiO2, like bandgap and index of refraction (TiO2 about 3.5eV and n 2.4). They are stable in sunlight and do not break down. This is why they are used in sunscreen, they both start absorbing not very far into the UV range. I am not sure which one is a better protectant. Some maker of TiO2 powders started offering very fine particle sizes (50-10 nm) for sunscreen manufacturers, but because the particles are so small, they scatter very little visible light, and appear clear. I do not know if the same sort of thing is offered in ZnO powder. As a transparent electrode material ZnO is usually deposited on glass. It is used in the same way as FTO and ITO, but I think it may have poorer conductivity for the same transparency. ZnO is used as a calalyst and being researched as a photo catalyst. 131.252.124.185 23:01, 29 September 2006 (UTC) David

According to Friends of Earth there are a wide range of products containing nano-particulate TiO2 and ZnO. http://www.foe.org/camps/comm/nanotech/nanocosmetics.pdf I am not too concerned over ZnO because it has been used in comparable size particles before without harm. ZnO is not a single molecule like C60 or carbon nanotubes, it slowly disolves in water to release Zn cations, which are a nutrient in small ammounts. Zinc Oxide health effects risk assessment. ecb.jrc.it/DOCUMENTS/Existing-Chemicals/RISK_ASSESSMENT/SUMMARY/zincoxideHHsum073.pdf 131.252.124.185 23:29, 29 September 2006 (UTC)David

Additions
I have attempted to edit the article based on discussions above and my own knowledge. Comments would be helpful.
 * ZnO (not the peroxide) is indeed the main "active" component of Calamine lotion. Physchim62 (talk) 07:44, 1 September 2006 (UTC)

Vandalism
Look at the first topic heading. Something is up. If anyone knows what it was originally titled, please revert it to the way it was. thanks.

Dubious
There were some dubious tags in the section about doping. I found journal references for all three cases, added them in, and removed the dubious tag. If there is another reason for this, feel free to put it back, but a note on the talk page here would be helpful. LouScheffer 06:37, 6 January 2007 (UTC)

The dubious tags were related to the misleading discussion on origins of n-typeness. It is stil an open topic in oxide community, and unresolved issues were stated as facts... I was about to add a note here, but you fixed the problem before I got that far ;-) Puel 06:48, 6 January 2007 (UTC)

The discussion on n-type character of as-grown ZnO was still wrong, so I have slightly modified this discussion. For example, the referenced paper by Janotti and van de Walle definitely does not propose that oxygen vacancies lead to n-type conductivity. Currently, there is no consensus about whether oxygen vacancies (or zinc interstitials) are responsible for the n-type character, so I added a reference to a paper that discusses all the possibilities. Also, there is a recent theoretical proposal (also by Janotti and van de Walle) that substitutional hydrogen impurities are the cause, so I added this reference too. NRLer 18:25, 26 October 2007 (UTC)

As is not the leading p-type dopant. The question is still open but many papers discuss N doping and a few use P doping. I'll post more references or make a correction when I have time, here are a couple papers using N doping: http://dx.doi.org/10.1063/1.2199588, http://dx.doi.org/10.1063/1.2166686, and using P doping: http://dx.doi.org/10.1002/adma.200502633. There are many more on N doping than either As or P, this needs a little more work —Preceding unsigned comment added by 68.6.68.153 (talk) 21:28, 29 February 2008 (UTC)

"... nitrogen is the most promising acceptor for ZnO..." http://dx.doi.org/10.1002/adma.200700083 —Preceding unsigned comment added by Mthardy (talk • contribs) 05:53, 2 March 2008 (UTC)

itch
Does Zinc oxide have anti-itch properties? If so, who discovered this, when, and what are the details of operation?-69.87.204.36 12:51, 27 April 2007 (UTC)

Taste
The fumes are dangerous (death is possible), metallic taste. But how does the ordinary solid-lotion form taste? Anything put on the skin will end up in the mouth occasionally, and it would be good to be able to recognize the taste!-69.87.199.151 17:38, 7 May 2007 (UTC)

Zinc Oxide as a surge arrester
Does anyone know more information about using Zinc Oxide rods as surge arresters for high voltage power lines? I know that the resistance drops as the voltage across it gets higher, so when it's connected between a power line and the ground power doesn't flow across it, but when a lightning strike hits the line the zinc oxide rod allows the energy to pass and then returns to normal. If anyone knows more info about this maybe you could put another heading on the zinc oxide page. Cheers Mike 121.45.173.178 07:20, 3 June 2007 (UTC)

Answer

I'm not sure how to use wikipedia but the above is correct. ZnO acts as an ohmic conductor up until a critical voltage, known as the breakdown voltage. After that the current flow increases dramatically. Hence it can be used as a surge protector.Once the voltage drops to normal it returns to having high resistivity. —Preceding unsigned comment added by 86.44.109.80 (talk) 21:38, 1 March 2010 (UTC)

ZnO toxicity as a nanoparticle
http://www.physorg.com/news63466994.html

This article suggests that ZnO nanoparticles appear as toxic as asbestos when tested on cell cultures (although the author of the study cautions that animal testing would be required to back this up). Is it worth writing this up, and if so should it be under a heading of Toxicity or Nanoparticles? Damburger 09:33, 6 November 2007 (UTC)

The article repeated the descredited opinion that nano-sized ZnO in sunscreen might be dangerous to health. I have inserted a reliable scientific reference to the contrary but retained the original references for balance. Please note that skin cancer kills, for example, 1800 Australians each year, therefore, any unjustified scare mongering that might discourage people from taking care in the sun is potentially dangerous.Mike in Oz (talk) 05:39, 10 August 2011 (UTC)

Real apps vs dreams
The big app for ZnO is in rubber with smaller uses including bactericidal ointments, dental cements, dopant for ceramics, animal feed supplements, catalyst for methanol synthesis, and electronic materials. The current article mentions these reasonably. The following do not appear to be applications: Such cutting edge stuff still mainly in the labs might be placed in a section on "research directions." Chem Abstracts lists >60,000 entries "mentioning" zinc oxide since 2000, so we need to be a highly restrained in citing literature. --Smokefoot (talk) 03:39, 15 January 2009 (UTC)
 * "ZnO layers are mainly deposited ..." this is a technique, not a use.
 * "Zinc oxide nanorod sensor..." not a use (yet)
 * "Spintronics" not a use (yet)
 * "Piezoelectricity .. in textile fibers [reported by] the Center for Nanostructure Characterization.." Not a use (a sales-pitch)

Depleted zinc oxide
Should be Depleted zinc oxide mentioned in the text?.--Stone (talk) 07:10, 14 February 2009 (UTC)
 * Done. Thank you NIMSoffice (talk) 08:02, 14 February 2009 (UTC)

Piezoelectric, pyroelectric
I question the claim that all three forms of ZnO exhibit both pyro and piezoelectic properties. The hexagonal form, space group #186, class 6mm certainly does, the cubic form, space group #216, class -43m should exhibit piezo but not pyro, and the cubic rock salt form, space group #225 is neither piezoelectric or pyroelectric, just like sodium chloride!.--Axiosaurus (talk) 09:53, 21 February 2009 (UTC)
 * This part was indeed sloppily written and was fixed upon this comment. Thank you.NIMSoffice (talk) 10:51, 21 February 2009 (UTC)

Use of zinc oxide in rubber manufacture
the major use is in rubber manufacture the best reference I have found so far is, Rubber Curing Systems, R. N. Datta, iSmithers Rapra, 2001,ISBN 1859573266 where it quotes an estimate of 100kt p.a. in western europe from the European rubber journal 2001, feb, page 20.

As for a chemistry mechanism- I was hoping to add a few words on the chemistry of the activation howvever it still appears to be not fully understood - a good review may be this which I don't have access to. Books accessed via google say basically the stearic acid dissolves the zinc oxide and an "intermediate" promotes vulcanization-- surely there must be something better out there.--Axiosaurus (talk) 13:21, 21 February 2009 (UTC)

popular culture
added ref to "Zinc Oxide and You" from the first film by ZAZ.99.151.167.110 (talk) 13:43, 19 July 2009 (UTC)
 * I trimmed the edit. IMHO, the mention of a movie with the title is appropriate but description of thematic aspects is less connected to an article zinc oxide. Here is a discussion of the topic: WP:POPCULTURE.--Smokefoot (talk) 14:12, 19 July 2009 (UTC)
 * I have restored the Popular Culture section. Contrary to the rather perfunctory WP:TRIV rationale cited for its removal, it is not a list but a single item of considerable relevance, nor is the information particularly miscellaneous. Zucker, Abrahams, and Zucker's choice of zinc oxide for their spoof was highly appropriate, well considered, and relevant (and they almost certainly knew it) as zinc oxide actually is a chemical with manifold uses, most of which are at the same time not particularly "sexy" nor widely known to the general public. Per WP:POPCULTURE: "one helpful test can be to look at whether a person who is familiar with the topic only through the reference in question has the potential to learn something meaningful about the topic from that work alone." Though the information is presented in a humorous way, Zinc Oxide and You correctly presents zinc oxide as a chemical with many and varied if relatively unglamorous uses, which is arguably a meaningful and relevant piece of information about the topic! Nude Amazon (talk) 07:23, 3 May 2010 (UTC)
 * Even assuming good faith, I would have thought it a rather elementary courtesy to check the talk page, especially when I carefully mentioned it in the edit summary! I am willing to discuss whether the rationale I gave above is sufficient to justify the inclusion of this reference or not, and I tried very hard to encapsulate its relevance as briefly as possible (given Smokefoot's apparent desire for brevity) with the phrase "reflecting its many varied but relatively unobtrusive and unglamorous uses" in the body of the article, and more extensively here on the talk page why I believe this reference is more than just random cruft. Whether one agrees with my rationale or not, Materialscientist's claim that it is "unclear why this deserves inclusion" at the very least strongly suggests that they did not even bother to look at the talk page :( Nude Amazon (talk) 08:07, 10 May 2010 (UTC)

Melting point and boiling point
The chembox had "1975 °C (decomposes)" for the melting point and "2360 °C" for the boiling point. This is an apparent contradiction because it cannot boil at a temperature above which it has decomposed. I have removed this data until it can be checked for accuracy. -- Ed (Edgar181) 18:55, 24 October 2009 (UTC)
 * Many materials decompose (sublimate) upon heating in air or in some other gases, well before reaching their melting points. Their melting and boiling points are measured under certain confining "pressure" (a layer of solid or liquid), or in specific atmosphere. Materialscientist (talk) 02:18, 25 October 2009 (UTC)
 * I haven't heard sublimation of a pure chemical compound being described as decomposition before (and it sounds like imprecise use of the terms to me). I see your point, though, that the reported decomposition and boiling temperatures could have been measured under different conditions.  If the boiling point is measured under some confining conditions, there should be some qualifier attached to the data in the chembox.  Looking at some of the references and external links in the article, I see 1975 °C described as the melting point, but not with decomposition specified, so perhaps that part should be removed.  -- Ed (Edgar181) 12:39, 25 October 2009 (UTC)

Zinc oxide and the meaning of WP:Secondary
This is a fine article however, most of the references are to journals. The effect is that this article becomes something of a "blog." In my interpretation, WP:Secondary urges us to seek reviews and books, not Journal of Applied Physics or Journal of the American Ceramic Society or Nanoletters, etc. An implication is that these primary sources should be replaced, over time, with more suitable book-y (and possibly fewer) references.--Smokefoot (talk) 14:26, 3 March 2010 (UTC)

referencing journals makes this article look legitimate. it is extremely well known that wikipedia's science, mathematics, and engineering articles are much more detailed and relevant than the "encyclopedic" nature of the overall site's goals. including information that is only referenced in journals may be a problem for print based encyclopedias, but this is an internet encyclopedia. thus it has the benefit of instant exchange of information and so therefore any issues associated with referencing new and potentially inaccurate work (which is the only concern with journal articles) is completely eliminated. any article that is subject to scrutiny or criticism can have its reference and the associated content removed within minutes.

I should add that the unavailable nature of 90% of these journals as free to the general public does not preclude their use as referencing material here in any way. the fact that most people can only read the abstracts does not mean that qualified authors cannot use their content as referencing material.... indeed, the fact that only students, academia, and some industry people have access to large numbers of journals INCREASES the likelihood that the authors citing such papers have legitimately read and understand them. this is, in contrast, to general audience articles which are referenced by authors who speed read, skim, and barely research their subjects, who may have never written a real research paper in their lives (having never attended a university), instead simply intending to pour their own point of view onto the hard drive of a server somewhere.

Solution Synthesis of single crystal ZnO (bulk not film)
Fred Lange at the MRL at UCSB has recently developed a method for solution deposition of ZnO from Zn(OH) and ammonia solution that results in single crystal ZnO (not nanorods or nanowires) in bulk (hundreds of nanometers thick). the synthesis appears to be similar to that used in nanorod synthesis, but the result is single crystal. Lange's group utilized a basic and well known method for growing homogeneous crystals (removing issues associated with large numbers of grain boundaries) to enhance the bulk single crystal nature of the grown material.

instead of simply growing the crystals on GaN or Mg(111) like most groups, his students used a special, but simple, technique in which the surface of the substrate is modified with a dry etch mask arranged into a pattern of small squares or long lines. the ZnO grows in a relatively uncontrolled manner on the exposed substrate, with large grain boundary density. then, as soon as the growing crystal reaches the "top" of the mask, the crystal begins to grow laterally.

this lateral growth is nearly free of crystal defects and continues to grow until surrounding lateral growths overtake one another and continue growing vertically. it is a well known technique, but I cant remember the name. he presented several TEM images of the resulting ZnO and you can clearly see how the laterally grown material has amazingly smaller grain defect density than the material grown directly from the substrate.

what you must realize is this: you can grow single crystal ZnO, in bulk and continuously, in water with ammonia. this is huge. I would not be surprised if he is going to be an extremely rich man within a decade. —Preceding unsigned comment added by 68.6.52.200 (talk) 15:59, 16 March 2010 (UTC)
 * Great material and congratulations on being so-current. Such material is ideal for an exciting blog or a journal, but Wikipedia is neither a blog nor a journal. Wikipedia's focus is on well-digested, contextualized  information, supported by references to reviews and books. See WP:NOT.--Smokefoot (talk) 16:06, 16 March 2010 (UTC)

Please see Popular Culture above
Upon further reflection I have discovered a potential good faith explanation why certain editors might have honestly felt "unclear" about my rationale for including the one crucial and blatantly relevant popular culture reference in the article, so in hopes of not having to repeat myself exhaustively, PLEASE LOOK FOR THE RATIONALE EARLIER ON THIS PAGE. Thank you Nude Amazon (talk) 08:07, 10 May 2010 (UTC)

Reference
The following reference was added to the references section, but it does not seem to support any specific statement. I'm moving it here in case there a use found for it. -- Ed (Edgar181) 21:35, 14 January 2011 (UTC)
 * 82 G. Amin et al. "ZnO nanorods–polymer hybrid white light emitting diode grown on a disposable paper substrate " (3 pages) [http://dx. Phys. Status Solidi RRL 5, No. 2–3, 71–73 (2011) / DOI 10.1002/pssr.201004446]

Suspicious Source - Can real scientists please help?
Long time reader/first time editor. Please help (and/or bear with) me. I'm taking issue with the statment in 'Applications, Medical,' and specifically "However, many sunscreens use nano zinc oxide (along with nano titanium dioxide) which does get absorbed into the skin." I just read an article in Scientific American that states "Of 15 scientific studies conducted by government, industry and independent researchers over the past decade, only one found that nanoparticles were absorbed by the skin of rabbits; none detected human skin penetration, even with an electron microscope." http://www.scientificamerican.com/article.cfm?id=do-nanoparticles-and-sunscreen-mix

So, okay science-folk, which is it?

Upon review of the source for this statement you'll find a press release from Friends of the Earth (FOE.) The second reference is an ABC News article. However, that article too, names its source as FOE. I'm not fond of this kind of circular sourcing in wikiarticles. I've read that FOE has been criticized for "engaging in unwarranted scare tactics with its latest fund-raising push," which references nanoparticles specifically. http://www.consumerfreedom.com/news_detail.cfm/h/882-friends-of-the-earth-enemies-of-the-truth. To be fair, the critic was probably an ultra-conservative corporate vulture. So who do I believe?

This is probably an easy question for someone who ACTUALLY knows what they're talking about. Is zinc oxide (in any size) absorbed by human skin? If the originally published statement is not correct, can someone please help edit it? I'm tired of being misinformed.

Qstnevrythng (talk) 07:14, 5 August 2011 (UTC)

Here is a reliable scientific source that refutes the anti-science:Mark E. Burnett & Steven Q. Wang, Current sunscreen controversies: a critical review, Photodermatology, Photoimmunology & Photomedicine 27, 58–67. So far, there is no evidence that nano-ZnO would penetrate skin under conditions of normal use. Please note that skin cancer is nasty and can kill. Mike in Oz (talk) 05:45, 10 August 2011 (UTC)

as catalyst for spltting water at high temperature?
this article describes an application using ZnO as a catalyst to yield hydrogen from water at high temperatures. Could someone please describe the chemistry of this process? 75.87.129.242 (talk) 06:05, 8 April 2012 (UTC)


 * http://www1.eere.energy.gov/hydrogenandfuelcells/production/water_splitting.html explains the process. 75.87.129.242 (talk) 06:10, 8 April 2012 (UTC)
 * There are many research papers on this topic, it is probably not appropriate for the encyclopedia article, which focuses more on theme closer to real world.--Smokefoot (talk) 13:09, 8 April 2012 (UTC)

Etymology of names
I'd really like to see an explanation of the more crpytic names, like "philosopher's wool". I haven't been able to find any credible sources on this subject. Attys (talk) 01:24, 21 April 2012 (UTC)

Article lede
Do we really need a paragraph in the lede about its potential use as a semiconductor? Surely the lede should focus on general information and important applications - which would be in rubber, as a pigment, as a biocide, in sun cream, etc. --Colapeninsula (talk) 13:14, 7 June 2013 (UTC)

Removing "Concrete" application
My reasoning is that the article claims that ZnO is used widely in the concrete industry. The source for this is a book from 1954. I can find no current sources to support this claim nor can I find any cement producers who currently use ZnO in their products. I wanted to make a Talk page entry to give the opportunity for someone to present current evidence if they find it. Thanks. Davidquick 11 (talk) 21:12, 5 March 2014 (UTC)

Skin safety
There seems to be much on this talk page about skin safety and nano-particle aspects, but none at all in the current article. The Sunscreen article at least has a little on the subject. Please add appropriate topical-usage health and safety information to the article. -96.233.19.191 (talk) 18:04, 11 July 2014 (UTC)

Incorrect molar mass
The listed molar mass of 81.408 g/mol is incorrect. The true molar mass is 81.379 g/mol. — Preceding unsigned comment added by 147.1.154.15 (talk) 16:31, 6 February 2015 (UTC)
 * Fixed, thanks. Materialscientist (talk) 23:01, 6 February 2015 (UTC)