Talk:Iron(II) hydride

Done with it

I did what I could with this page. I have checked the references provided but did not look for additional ones. Some things would need improvement:

• Discovery - who, original ref.
• Temperature of decomposition.

All the best, --Jorge Stolfi (talk) 23:38, 18 February 2013 (UTC)

Systematic name

I've had an epiphany, the "(4•)" should be removed from the systematic name. My reasoning, it is an artifact of internal electronic arrangement. This arrangement does not affect the identity of the substance, only the nature. Meaning, whether dihydridoiron is in its quintet groundstate, or a triplet excited state, it is still dihydridoiron.

Other molecules with an odd number of unpaired electrons are exceptions. Every possible arrangement will leave a minimum of one unpaired electron, so a "(•)" should be retained. This means that "(3•)" should be replaced with "(•)". Plasmic Physics (talk) 14:11, 13 June 2013 (UTC)

Amphotericity section

Amphotericity section bears an uncanny resemblance to similar sections in borane and gallane, and like them is unreferenced.

Lewis amphotericity, yes this molecular form should act as a lewis acid but a lewis base??

Secondly it may be worth looking at the chemistry of the well known H₂Fe(CO)₄ and its preparation, it is an example of an Fe(II) dihydride complex. Somewhere there will be references that support (or not) the very specific claims made in this section.

Axiosaurus (talk) 12:33, 21 October 2013 (UTC)

whilst writing this I see that a reference has appeared, the one chosen isn't that apprprate in my view a better one would be one that quoted the known pKa of H2Fe(CO)4. Interesting problem is that the stability of the anion is key in deprotonation and HFe(CO)4- is stable- I am sceptical about the stability of FeH^- which presumably is the anion in this example as no solvent is specified. Axiosaurus (talk) 12:49, 21 October 2013 (UTC)

A further reference has appeared- the reference aplies to a complex of FeH2 complex- so it appears that this section actually refers to the chemistry of generic complexes, H2FeLn (where L appears to be a neutral ligand) rather than molecular FeH2. The acid/base of the dihydride complexes of iron and other t. metals is an interesting area and should be dealt with in a generic article. Axiosaurus (talk) 21:57, 21 October 2013 (UTC)

Why do you suppose that free FeH
₂ is that much different from its neutral complexes? Furthermore, not all t.m. dihydride complexes have the same acid/base chemistry, e.g. FeH
₂ complexes are predominantly acidic, whereas many others are predominantly basic. Plasmic Physics (talk) 23:51, 21 October 2013 (UTC)

Well. Different from its neutral complexes- consider the carbonyl complexes. The back donation of electron charge in these is known to cause decrease in CO stretching frequency- the charge delocalisation is seen by some as contributing to the stability of the anions and therefore affecting the pKa of the neutral species. It would be surprising indeed if the complexing ligands did not affect the overall chemistry of a complex. The chemistry of molecular FeH₂ is unknown, the section in question misleadingly suggests otherwise. What is very wikipedian about this discussion is that misleading unreferenced information can be added to an article and yet we are obliged to discuss its removal. Axiosaurus (talk) 07:03, 22 October 2013 (UTC)

I would request that we remove this section altogether. I asked for a reference on Plasmic's talk page and this appeared. The reference is about [FeH₂(dppe)₂] a completely different molecule. Applying the result from this (or the carbonyl hydride) to FeH2 is original research. Any solvent that has OH- or H+ ions is going to react with FeH2 and I do not believe that research has been done on this yet. I have got a google alert running to email me new research for the iron hydrides, and almost all are more complex molecules and not about the simple hydride. Graeme Bartlett (talk) 10:10, 22 October 2013 (UTC)

Copper sulfate seems to be doing just fine treating the neutral hydrated complex as chemically equivalent to the anhydrous form. Plasmic Physics (talk) 12:14, 22 October 2013 (UTC)

Not a good comparison! Really you must do better!Axiosaurus (talk) 13:29, 22 October 2013 (UTC)

Well that because copper sulfate and the hydrate are often interconverted. Ther are not the same substance either, but because water is so common hydrate will be connected. Graeme Bartlett (talk) 21:02, 22 October 2013 (UTC)

If we're going to be pedantic about this, it would be easier to just fix this by just replacing FeH
₂ with FeH
₂L
_n below the section that deals with its Lewis-amphotericity. (That section deals with free iron(II) hydride). Plasmic Physics (talk) 22:42, 22 October 2013 (UTC)

If we do extend the article to cover these dihydride derivatives then I think it can be included, but it has to be clear what the topic molecule is, and not speculate that it applies to FeH2 itself. Graeme Bartlett (talk) 11:42, 23 October 2013 (UTC)

Shall I go ahead and make the changes then? Plasmic Physics (talk) 12:26, 23 October 2013 (UTC)

why not it will improve the article! Also you should read up on lone pairs and why t metals are considered not to have them. Axiosaurus (talk) 15:42, 23 October 2013 (UTC)

The words "transition metal" does not even feature in Lone pair. Plasmic Physics (talk) 21:50, 23 October 2013 (UTC)

Correct. They are not mentioned for a reason, which is not made clear. That article is not that good in my opinion. Look at other sites, try Mark Winters. In simple terms its all about shape directionality etc. of the lone pair orbital- p and sp hybrids have the right characteristics d orbitals don't. The general opinion is that t metals do not have lone pairs as such- which is the rationalisation for t metals not being lewis bases (generally)-- as always there are exceptions -- look up Z-ligands. Anyway this is why I do not think it is obvious that FeH2 is a Lewis base and the statement that it is, IMO, does not meet the WP:BLUE SKY criteria.Axiosaurus (talk) 08:49, 24 October 2013 (UTC)

Fine, I'll remove it. Plasmic Physics (talk) 09:27, 24 October 2013 (UTC)

Ok. We are getting there slowly. The use of the word solvate to describe complexes is v. odd- this implies that carbonyls maybe made by reacting metal ions in liquid CO which of course is not the case. There is a lot of unreferenced general iron dihydride chemistry quoted and this needs references. The amphotericity section is speculative but written as if the experiments had been carried out- which is naughty.Axiosaurus (talk) 15:01, 26 October 2013 (UTC)

Dubious statements

• Now a new reference from Morris has been added to say that a solid has been made. However this appears to be a more complex compound involving ether and mesityl, and so not justifying the bold claim in the lede.
• Also the manufacture of an indium compound looks to be in error.
• Use of the term ferrane needs a reference, as this term does not seem to be used in the citations.
• The Acidity section looks to be original research as in the previous section. (I have removed this, there were no citations to support this concept).
• Being a colourless gas is dubious. It would not exist under standard conditions like this, and I suspect that a bulk amount of this molecule would be coloured, as there is an absorption spectrum. Some have used the NIST chemical book to find statments like this, but it seems that the statements here are unjustified.
• FeH₃ may need qualification.
• Decomposition to iron nanocrystals has started life with a citation needed, so that must have come from somewhere!

Graeme Bartlett (talk) 02:22, 10 December 2014 (UTC)

The compound made by Morris et al was contaminated, hence the complicated formula. "Indium" was meant to be "iron". Ferrane(2) is a systematically constructed name, and has now been replaced with a more agreeable name. The acidity section is not original research, as it has a reference. Paraphrasing is a key concept that is relevant, and has been accepted elsewhere after discussion ad tedium. That FeH
₃ needs qualification, requires clarification. Plasmic Physics (talk) 02:57, 10 December 2014 (UTC)

I removed the 'colourless' term, but it's hardly dubious. Crystal field theory indicates that the compound should indeed be colourless, as both excitation energies correspond to the infrared part of the spectrum, not to anywhere in the visible spectrum. Based on this method, it is entirely likely to be colourless. Plasmic Physics (talk) 12:05, 10 December 2014 (UTC)

That has improved a couple of issues. I was hoping there would be a citation for the decomposition, if you have the refernce handy. I had some of the documents accessed before, but not handy at the moment. Leah Morris's formula has an x and y in it. But what are the values of x and y? Are they minute and so the material is meerly contaminated, or do they indicate that ether is an intrinsic part of the material? (I am thinking that if we give this enough attention we can get it to a good article status!) Graeme Bartlett (talk) 12:59, 10 December 2014 (UTC)

I don't know about minute, but R and ether are definitely not intrinsic components, they paper addresses them as contaminants in an explicit way. Plasmic Physics (talk) 20:49, 10 December 2014 (UTC)