Talk:Sodium ferrocyanide

Safety

What is the safety of this compound, when added to food-grade salt? Badagnani (talk) 20:53, 21 January 2008 (UTC)

Decomposition

The article states that Sodium ferrocyanide decomposes at 435°C, but to what? Does anyone know? I would imagine that it would decompose to sodium cyanide and iron cyanide, but the article states that it can "photodecompose to release hydrogen cyanide gas". How can it decompose to hydrogen cyanide gas when there is no hydrogen in the compound? 86.167.77.158 (talk) 15:37, 15 November 2009 (UTC)

I can only guess (correct me if I'm wrong) that decomposition assumes presence of water or its vapors. Then it would leave something like oxides and hydroxides of Fe and Na and HCN gas. In vacuum, the products should be sodium cyanide (NaCN) and iron. Materialscientist (talk) 01:36, 16 November 2009 (UTC)

MS, you're probably right about the water and decomp. The potassium salt is the main one commercially, I think. Let me look into it.--Smokefoot (talk) 01:55, 16 November 2009 (UTC)

bond energy of Fe-CN bond

The article vaguely states that "the cyanide molecules are tightly bound to the iron". That is meaningless without a point of comparison, so I have tagged it for clarification. A sourced numerical value for the bond energy of the Fe-Cn bond would be much more informative.

I reverted this edit by Smokefoot, because it replaced one vague phrase with another one: "the cyanide ligands do not dissociate readily".

--50.53.54.144 (talk) 21:01, 13 August 2015 (UTC)

New editors are often slightly idealistic or pedantic, depending on one's perspective. WIki-chemistry describes a vast of number of chemical compounds and chemical reactions. It would be ideal if every statement about reactivity cited thermodynamic and kinetic parameters. The reality is that such data are often known only qualitatively. So editors here, like professional chemists in general, are a little loose with such statements. Our choice is that we are either a little vague or we dont write articles, you can't have it both ways.

An advanced inorganic textbook is not going to have bond energies corresponding to [Fe(CN)₆]^4- to [Fe(CN)₅]^3- + CN^-. A research article might discuss a computational experiment, or an experiment conducted by some gas phase technique. Probably some very specialized report evaluates the equilibrium for [Fe(CN)₆]^4- to [Fe(CN)₅(H₂O)]^3- + CN^- and from those data, some sort of Fe-CN bond energy could be inferred.

So one is encouraged to look around Wikipedia before jump in, demanding data. Another idea is to become familiar with the concept of inert vs labile coordination complexes, a concept discussed in most beginning inorganic chemistry testbooks. It is that concept that allows chemists like me to make broad assertions without citing specific data. The architypal inert ions (the ones favored by Alfred Werner) are low spin d6, exemplified by hexacyanoferrate(II).

The above having been said, there no doubt are better ways of conveying the inertness of the ion in question. This topic could be further discussed here. But please don't go around demanding data without checking context and learning basic concepts.--Smokefoot (talk) 22:41, 13 August 2015 (UTC)

That's a long way of saying that you don't know, but the point of this is to explain to readers why sodium ferrocyanide is not immediately toxic when consumed in the concentrations that would be found in table salt. A quantitative qualitative comparison with NaCN might suffice. --50.53.251.83 (talk) 01:44, 14 August 2015 (UTC)

Well, one way to improve Wikipedia is to prove one's ability to write some decent content. So go for it! Up to it? --Smokefoot (talk) 03:11, 14 August 2015 (UTC)

The Fe-CN bond appears to be the subject of ongoing research, so I am replacing "quantitative" with "qualitative" above.

Source: Chemical Bonding in Aqueous Ferrocyanide: Experimental and Theoretical X-ray Spectroscopic Study (2014).

--50.53.251.83 (talk) 03:19, 14 August 2015 (UTC)

The article on Ferrocyanide has a sourced sentence that I would propose using, possibly with some modifications. It is still vague, but Holleman & Wiberg sound like a very reliable source. NB: I have not looked at this source. Do you have access to it?

"Although many salts of cyanide are highly toxic, ferro- and ferricyanides are less toxic because they tend not to release free cyanide."

Source: Holleman, A. F.; Wiberg, E. (2001). Inorganic Chemistry. San Diego: Academic Press. ISBN 0-12-352651-5.{{cite book}}: CS1 maint: multiple names: authors list (link)

--50.53.251.83 (talk) 03:36, 14 August 2015 (UTC)

Re "The Fe-CN bond appears to be the subject of ongoing research" yes, probably many hundreds of publications (including one by me). Its a big area. Your suggestions look great - stick them into the article and keep going. Happy editing. --Smokefoot (talk) 03:47, 14 August 2015 (UTC)

Done. The article has links to ferrocyanide, cyanide, and toxicity, so I am going to say this job is done. :-) Thanks for your input. --50.53.251.83 (talk) 05:22, 14 August 2015 (UTC)