Talk:Prussian blue

Chelation
The article says that Prussian blue is used for chelation therapy. Prussian blue is indeed able to sequester certain metals, but it doesn't do so through chelation. Chelation requires a multi-dentate ligand to bind to a metal. Prussian blue sequesters metals by absorbing them into its lattice, which isn't the same thing. Unless someone wants to explain why the term "chelation" should stay, I'm going to remove it from the article. —Preceding unsigned comment added by 128.227.179.89 (talk) 21:44, 13 February 2009 (UTC)

Tyrian Purple
The article mentions Tyrian Purple as fading over time. This is not true, with the wikipedia article for it stating that exposure to sunlight and weathering, which usually destroy most pigments, actually strengthens and brightens the color. Other murex snail-derived dyes also have similar properties, often only showing their color after light exposure. (UTC)  — Preceding unsigned comment added by 218.214.214.252 (talk)

Unqualified use of color coordinates
As any formally trained color scientist would confirm, it is inappropriate to use unqualified color coordinates to specify a color appearance. In the Prussian Blue article, as I would guess all the other color-related articles, there is a box on the upper-right of the page that pretends to state the color coordinates of the color in RGB, CMYK, HSV and Hex values. This is wholly incorrect. RGB values in themselves cannot depict color appearance. In order to do so, the RGB triplet has to be connected to physical reality through, at the minimum, the definition of the RGB color space used, the white point of the illuminant, and in certain cases, the gamma function. The ICC specifications can help one understand what these requirements are. If Prussian Blue has such and such color coordinates, they have to be qualified as, for example, in AdobeRGB color space. Better still, linear XYZ color coordinates should be used. Furthermore the conversion of RGB to CMYK is wholly dependent on the particular transfer functions used for a specific set of inks and paper combination - the idea of posting the CMYK color coordinates for a physical color appearance is naïve at best and mostly preposterous.

As such the article runs contrary to the most basic precepts of color science, and is wholly misleading to uninformed readers. Trying to digitally reproduce the appearance of Prussian Blue using the information contained herein will not work at all. (unsigned comment by User:Ppanzini on 2006-11-21T07:50:27)


 * Then please conduct a series of independent tests with all the information needed, publish it, cite it here, and change the Color Composition section. In the meantime, it will do as an approximation. -Toptomcat 22:40, 24 November 2006 (UTC)


 * I agree whole-heartedly with the criticism of Dr. Bigwig Color Expert above. If you think that you can do any better than the article says, Then Do It. Otherwise, there are No Grounds for your wretched belly-aching! Until you can come up with something better, the present will do as a good approximation.
 * Everyone else, please note that the RGB (red, green, blue) coordinates are each normalized to a maximum value of 255, and that the color scale is a linear one from 0 to 255. There is nothing magical about the number 255, since the simple eight-bit binary number 11111111 equals to 255 in decimal numbers. Also, as it commonly used in such color scales for use in digital computer displays, (0, 0, 0) corresponds to deepest black; and (255, 255, 255) corresponds to the whitest of whites.74.163.48.102 (talk) 03:40, 2 October 2008 (UTC)


 * {ping|JHFTC|Ppanzini}} I realize that this is an ancient thread, but... Ppanzini is absolutely right, and your reactions to his comments are wholly inappropriate. True, Ppanzini doesn't seem to know how we do things on Wikipedia, but still, Please do not bite the newcomers. Giving him some guidance on how to contribute constructively would be have been far more helpful than unreasonable suggestions ("please conduct a series of independent tests") and criticism. There are surely lots of existing good reliable sources for the CIE/NCS color of Prussian blue and other colors, and Ppanzini could have helped us find them, and use them appropriately. --Macrakis (talk) 19:26, 20 January 2020 (UTC)


 * The coordinates that were given were cyclic referenced back to Wikipedia's 2010~2012 list of colors article. Compare and 2010 . Might not be the exact version it was based on, but close. Pale Aqua  (talk) 13:42, 6 June 2022 (UTC)

About the Molecular Weight of Prussian Blue
I wish that I could help more precisely with this one, but not being a chemist, a chemical engineer, or a medical doctor, I can't give the actual numbers. (However, I am an electrical engineer and a mathematician - with master's degrees in both - and I can tell when numbers don't make too much sense.)

Considering that the molecular formula of Prussian blue is Fe7(CN)18(H2O)x, where the 7, the 18, the 2, and the x are subscripts, and 14 <= x <= 18, to say that its Molar Mass is 859.23 g/mol is to an absurd level of precision. As x varies between 14 and 16 (inclusive), depending on the water content of the substance, the Molar Mass varies by a significant percentage. So, the Molar Mass should be expressed as a range, with a minimum value and a maximum value.74.163.48.102 (talk) 05:03, 2 October 2008 (UTC)


 * The formula given in the article on which the molar mass is based is the idealized formula for the iron and cyanide ions that actually make up the Prussian blue. Prussian blue will also absorbs water molecules and cations into its lattice if it has the chance to do so. Whether or not the water molecules and cations that are absorbed into the lattice count as being part of the Prussian blue for purposes of figuring out its atomic mass is debatable. Certainly in journal articles you will often see the cation and water ratios listed as part of the formula, since many of its properties depend on how many water molecules and extra cations it has. —Preceding unsigned comment added by 128.227.179.89 (talk) 21:52, 13 February 2009 (UTC)

Prussian Blue in concentration camp remains
The only place I ran across Prussian Blue outside of art history or a chemistry class was in a discussion of proving certain buildings were used as gas chambers in concentration camps - as I recall, the claim was that Prussian Blue formed on the rusted iron drain pipes of the shower rooms that had been repeatedly exposed to the cyanide.

Is this a subject we want to include in this article, or do we not want to touch that? TaigaBridge 21:56, 16 May 2007 (UTC)
 * It's certainly interesting. Wikipedia's not really about avoiding controversial subjects; all we care about is one thing. Can you find a source for it? -Toptomcat 04:45, 6 July 2007 (UTC)
 * Try http://www.holocaust-history.org/auschwitz/chemistry/ ImmunolPhD 12:11, 20 July 2007 (UTC)
 * I'm afraid that's a broken link for me. -Toptomcat 18:26, 25 July 2007 (UTC)
 * Works fine for me and is fairly thorough/reliable seeming. I only took a cursory look though. Try the link again maybe? --Cheeser1 21:59, 25 July 2007 (UTC)
 * I agree it should be included, it strikes me as odd it's been left out. Careful with citations though, it's a hot-button subject so all references should be scrupulously cited.218.102.83.254 (talk) 07:31, 31 December 2008 (UTC)
 * Yes, please please include it. This is a very historically important fact Science Is My Life (talk) 00:38, 6 March 2021 (UTC)
 * Why hasn't this been done? Jellinator (talk) 06:59, 7 June 2021 (UTC)

Zyklon B
I've copied across material from Zyklon B. Please edit as needed.  Ty 

Staining
Prussian blue is also known as a histology stain, to test for iron. In fact, this page is linked from the histology page, section "staining" http://en.wikipedia.org/wiki/Histology#Staining

Info on the stain can be found at: http://cancerweb.ncl.ac.uk/cgi-bin/omd?Perls'+Prussian+blue+stain

Perhaps a new section titled "Staining", or a new link option for "Prussian Blue Iron Staining"?

68.163.33.106 03:47, 1 September 2007 (UTC)Mko

Why are there two sections for the same thing?
There is an "other properties" section and "culture" section. Why? First, things like its being used for treatment of ingestion of cesium should be in the medical properties, and medical properties should NOT be considered culture. Second, cesium plays an insignificant role in pop culture. In my opinion, the "culture" heading should be eliminated and the text within that section should be moved to the appropriate places in the article, or separated into "uses" and "properties". —Preceding unsigned comment added by Rocketman768 (talk • contribs) 02:37, 17 October 2007 (UTC)


 * Agreed, the culture section contains trivial items and has been renamed and trimmed appropriately. Ciotog 14:20, 4 November 2007 (UTC)

Prussian Blue On Prussian Uniforms?
The uniforms of the Prussian army.... wern't they Prussian Blue? —Preceding unsigned comment added by 86.151.178.205 (talk) 18:56, 13 March 2008 (UTC)

Holocaust?
Where on Earth is the stuff about Prussian Blue and the Holocaust as the poster above mentioned? —Preceding unsigned comment added by 86.128.148.9 (talk) 21:29, 27 May 2008 (UTC)
 * It might be b.s. (i would imagine it is, the holocaust is well documented and denial of it is a fringe movement) and therefore hard to find. Be good to mention the controversy and any locatable facts though.218.102.83.254 (talk) 07:33, 31 December 2008 (UTC)


 * I was able to see that link and the paper debunks the holocaust deniers claims (point by point), the pertinent statement is in the Abstract where it states:


 * ... The arguments made by deniers are distortions of fact. The deniers misrepresent the statistics of the dead, and misinterpret air photo evidence. The properties of hydrogen cyanide from Zyklon B are consistent with its use as an agent of mass murder. The fact that Prussian blue is prevalent in delousing facilities but not in homicidal chambers is not evidence that no gassings occurred. In fact, Prussian-blue formation is extremely sensitive to conditions, and it is quite reasonable that Prussian blue formed in the delousing chambers but not all of the gas chambers used for murder. ...
 * And in the Introduction;
 * ''Holocaust denial, known in Germany as the Auschwitz lie, has been gaining exposure in recent times, in part perhaps, because of the growth of the Internet. Deborah Lipstadt in her thought-provoking book Denying the Holocaust argues persuasively that the existence of the Holocaust is not a matter for debate: there is nothing to debate; it is a historical fact.

''
 * However, the discussion on Prussian Blue formation toward the bottom of that paper seems a little obscure. That could easily be my misunderstanding of the subject matter though. I just wanted to clear up that the paper is in fact accessible and is not a holocaust deniers paper (quite the contrary.) 2605:A000:1402:4025:457:CAE1:908:2F08 (talk) 22:53, 13 September 2015 (UTC)

Whitespace?
I'm seeing a big chunk of whitespace next to the chemistry infobox, and the text of the article begins only next to the color infobox. I had a look at the page source but couldn't figure out what was causing that. Would someone who understands formatting better than I do take a look at that? (I'm on IE 6.0, WinXP). Chuck (talk) 21:01, 5 June 2008 (UTC)


 * Looks perfectly okay on WinXP/Firefox, but it broke on WinXP/IE 7. Moving it down appears to have done the trick.--Rifleman 82 (talk) 21:17, 5 June 2008 (UTC)

"New Cyanotype"
The text regarding "New Cyanotype" ("New Cyanotype, [...] gives increased tonal range and reduces exposure times.") seems to be poorly done and misplaced:

1. It should be relocated to the "Cyanotype" article, as it is a modification of the cyanotype process and has little to do with Prussian Blue per se.

2. The external link should be to the page that gives the New Cyanotype process (http://www.mikeware.co.uk/mikeware/New_Cyanotype_Process.html), not to the main page of the site (http://www.mikeware.co.uk/), which has no information on the process.

3. The sentence does not fit with the flow of the text and is not adjacent to the one other sentence in the article regarding cyanotypes.

4. That sentence was added in an edit that made no other change, attributed to IP addr 62.56.118.116.

Indeed, looking at the External Links section of "Cyanotype", I see a link to New Cyanotype which has these problems corrected.

Hence, I am undoing the change that added this sentence. DWorley (talk) 20:00, 2 August 2009 (UTC)

Uses
I'm going to add the Prussian blue assay for total phenols Jasoninkid (talk) 15:25, 19 December 2009 (UTC)

Unclear "properties"
The sentence "It is insoluble, but the crystallites tend to form a colloid." is nonsensical since no (class of) solvent is specified. --Belg4mit (talk) 02:28, 26 April 2011 (UTC)
 * Well its not nonsensical, so kill that. But it might be unclear.  The default solvent for humanoids is water.  --Smokefoot (talk) 02:33, 26 April 2011 (UTC)

Crayola
Should the article have information about Crayola renaming their "Prussian Blue" color? It's trivia but relevant. 99.236.208.169 (talk) 17:21, 2 October 2011 (UTC)
 * I dont think that the editors in this project are interested in any more trivia since the basic concepts are already difficult to understand and the trivia, aside from being trivia, does not help illuminate readers. In the articles on Crayola such trivia might be more appropriate. At least in my opinion. --Smokefoot (talk) 17:44, 2 October 2011 (UTC)

How first made?
Before men knew how to make cyanide, how was Prussian blue made? What ingredients and how were they treated? Anthony Appleyard (talk) 06:12, 29 January 2012 (UTC)


 * Apparently dried blood can be cooked with strong base to make potassium ferrocyanide. Don't ask me how, but that's the medieval recipe. Once you have that, adding any soluble iron salt yields Prussian blue. In the first accidental synthesis the base was potash and the blood came from the animal oil. The iron salts contaminating the alkali provided the rest.  S  B Harris 06:34, 29 January 2012 (UTC)

Medical Uses Section Erroneous Information
Towards the end of the Medical Uses section it indicates Prussian Blue has been removed from the US markets because safer medications are available. The citation is pending.

I would like to point out the following government FDA link that was pointed to via a link through the CDC link, I provided both below, that indicate this may be false. http://www.fda.gov/Drugs/EmergencyPreparedness/BioterrorismandDrugPreparedness/ucm130337.htm

http://emergency.cdc.gov/radiation/prussianblue.asp

The FDA link was last updated in 2011 and the CDC page was last updated on 2014.

Additionally, if you look at the FDA link (dated Jan 2015) for Ca- DTPA and Zn-DTPA ( a different treatment) you will find the following question/answer; - 10. How does this relate to FDA’s previous findings that Prussian blue may be safe and efficacious for people internally contaminated with radioactive materials?

Both Prussian blue and the DTPA products are drugs intended to enhance the elimination of radioactive materials from the body. The drugs differ in chemical composition, routes of administration, side effects, and types of radioactive materials that they eliminate from the body. Prussian blue is administered by mouth while the DTPA products are injected in the blood stream or inhaled. The main side effects of Prussian blue are constipation and upset stomach. The main side effect of the DTPA products, especially Ca-DTPA, is a decrease in levels of certain essential nutritional metals. Prussian blue remains in the intestine and binds radioactive cesium and thallium. DTPA products circulate through the blood stream and bind radioactive transuranium elements (i.e., plutonium, americium, curium).

http://www.fda.gov/Drugs/EmergencyPreparedness/BioterrorismandDrugPreparedness/ucm130314 Found via http://www.fda.gov/Drugs/EmergencyPreparedness/BioterrorismandDrugPreparedness/ucm063807.htm Dated Feb 2014 --

I could find no statement that Prussian Blue has been removed from the market in the USA or elsewhere. I would recommend that statement be removed unless a current citation can be found. Thanks! 72.128.208.82 (talk) 22:13, 13 September 2015 (UTC)

The Joy of Painting
I think that there should be a reference to Bob Ross' use of this color oil paint in his TV show, The Joy of Painting. It's a well-known program, and not just a "cheezy US? TV ref" as Smokefoot wrote in their undo. If not in the body of the article, it should be included under See Also. Hameltion (talk) 23:57, 21 May 2017 (UTC)
 * Doesnt the figure showing Vincent van Gogh's use of PB in a famous picture establish the importane of this pigment? See caption: "Vincent van Gogh's Starry Night uses Prussian and Cerulean blue pigments. Although he was never on American TV, van Gogh carries more weight, it seems. Is the point to beef up its role in oil painting or to highlight the TV character? Most of the non-US readers are not going to know who Ross is nor heard of his TV show..

I suspect that any modern artist who uses dark blue uses PB, but would need to verify. --Smokefoot (talk) 00:45, 22 May 2017 (UTC)
 * That seems fair, I was just hoping to include Ross. Your reasoning makes perfect sense. --Hameltion (talk) 00:51, 22 May 2017 (UTC)

External links modified
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Really?
You want a list of everyone who dyed with Prussian blue?--Smokefoot (talk) 12:13, 10 January 2019 (UTC)
 * No, just the significant ones  (and this wants to be on the article talk page, not here).  Read the linked article at Tekhelet. The appropriate dye for them is simultaneously a matter of some religious importance, yet also unknown.  For prussian blue to have been considered in such a way (and really it's a pretty poor dyestuff) would seem significant.
 * Likewise we're going to mention its use for engineering drawings, because that's both driving etymology and also the light-sensitivity is technically unusual. Andy Dingley (talk) 12:20, 10 January 2019 (UTC)
 * Thanks for the clarification/explanation. The use of Prussian Blue in dying various items should probably (IMHO) be in the articles about those items not the Prussian blue article itself.  My 2 cents.--Smokefoot (talk) 12:42, 10 January 2019 (UTC)

Requested move 22 January 2019
There's currently a move discussion at Talk:Prussian Blue. While it doesn't directly affect this article, it may be of interest to those who watch here. 62.165.227.102 (talk) 11:05, 23 January 2019 (UTC)

Illustrating the structure
I know this is a complicated topic, so it'd be good to get other views before I add anything inaccurate to this article. I've made some images of the structure of 'normal' and dehydrated Prussian blue based on the 1980 neutron diffraction study:



I personally find a text description of the structure hard to make sense of without some kind of image to enhance it, even if the image cannot show every subtlety. Is there a way we could incorporate these, or similar, images into the article?

Ben (talk) 13:18, 7 February 2021 (UTC)


 * Its a difficult topic. It looks like your images consist of a disorder model for nonlinear Fe-CN-Fe links.  The structural work is not with single crystals, and may be a little shakey. So I wonder if these links are so extremely nonlinear.  One rarely sees such nonlinearity in molecular species with M-CN-M links (unless M is alkali metal).  But if you are semi-convinced of the nonlinear links, just mayb pick one subset of the disorder so that the Fe's are interconnected by rods, not X's.  Two of the images show intercalated ions and water. Good. Those components are relevant to the ion exchange properties of PB, i.e. its application to remediation of 137Cs spills. Very welcome but challenging service to the community. --Smokefoot (talk) 15:07, 7 February 2021 (UTC)

Thanks Smokefoot, really helpful thoughts. I have no special attachment to the dehydrated structure, so it's probably easier to leave it out than pick one component of the disorder. Glad to hear the hydrated structure is reasonable. Is there any value in starting with simplified models and building the reader up to the complex, disordered reality? If so, the following may help:



Ben (talk) 16:47, 7 February 2021 (UTC)
 * Ben, Your images look good to me. Here is a ChemDraw of the defect-free material.

.--Smokefoot (talk) 17:01, 7 February 2021 (UTC)

Looks great! I've just added a selection. Many thanks. --Ben (talk) 18:55, 7 February 2021 (UTC)