Talk:Copper hydride

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The article needs to be rewritten to fit with modern consensus and current research, to reflect the distinction of alloy and compound. Moreover, since the article is predominantly about the alloy, it should not have a chembox; steel, and bronze do not have chemboxes. Plasmic Physics (talk) 22:51, 4 March 2013 (UTC)

The page doesn't seen to be predominantly about the alloy, it only mensions it as a bullet-point at the bottom(?). Is the alloy important, I've never encountered it (is it 'normal' or something formed by beta-radiation?).Project Osprey (talk) 09:26, 6 March 2013 (UTC)
The red substance with the wurtzite structure is the alloy. Plasmic Physics (talk) 09:33, 6 March 2013 (UTC)
If the alloy is comprised of H and Cu in a 1:1 ratio how does it differ from the chemical compound? (Does it not have to be metallic for it to be an alloy? The reference provided doesn't seem to be describing a metallic compound) Project Osprey (talk) 10:10, 6 March 2013 (UTC)
The alloy does not occur strictly, but it does occut commonly as 1:1. As a mixture, the constituents of the alloy retains their respective chemical properties and makeup. Moreover, it can be separated by physical (mechanical or thermal) means. Conversely, the physical and chemical properties of the chemical compound differs from those of their constituents, and the components of the compound can only be separated by a chemical reaction.
The alloy is metallic, and electrically conductive. For one, have noticed that the compound has a sublimation point of -20 deg C? Plasmic Physics (talk) 10:47, 6 March 2013 (UTC)
  • I'm afraid I don't agree. If the constituents of the alloy retained their 'natural' chemical properties then the alloy would have to be a non-classical dihydrogen complex made up of Cu0 and H2. A material like that could be ground up to release the starting materials in their natural form. CuH is different, you would need a chemical change to regain H2. Heating it does achieve this, but it is a redox process not a physical one. (BTW, I'm not saying that info on the alloy shouldn't be added. I just don't want to generate confusion by having 3 things, all with the same name, all made from the same stuff in the same amounts, somehow all be different)Project Osprey (talk) 12:42, 6 March 2013 (UTC)
I should specify that it is an alloy of metallic hydrogen and copper not dihydrogen. There is no chemical bonds within the red powdered alloy, I assure you it is a mixture, not a compound. This confusion is exactly what I wanted to avoid with split articles. (There are only two different uses of the term 'copper hydride', not three) Plasmic Physics (talk) 21:59, 6 March 2013 (UTC)
  • What you call a alloy I call a chemical compound. The hydrogen is involved in metallic bonding, that's why this stuff doesn't react violently with water, as any normal hydride would. In this respect it's similar to Palladium hydride and certain other transition metal hydrides.
While I'm happy with you calling this an alloy it is wrong to say that it's just a physical mixture of the two things, there are bonds here, it is a discreet chemical compound. I do not believe you could put this through a sieve and collect a pile of copper one side and a pile of metallic hydrogen on the other. Being an alloy doesn't preclude it having chemistry, steal is an alloy but can contain discreet chemicals like cementite. Equally the diatomic species should just be it's vapour phase and to be honest I'm dubious of the sublimation temperature you've provided. Is there any chance you could provide some references for that... and for it being possible to separate the constituents by physical action?Project Osprey (talk) 01:47, 8 March 2013 (UTC)
Well, using your logic, I want to see you try and separate steel with a sieve. Moreover, if you separate the hydrogen from the copper, you would not have metallic hydrogen as it is not table at standard conditions. Indeed, being an alloy does not preclude it from having chemistry, but it does preclude it from being a chemical compound, as per our own article on the matter (no pun intended). Separation by physical action, implies that applying force to the alloy (tension, shear, etc.) increases hydrogen mobility, thus hydrogen will precipitate our faster, while heating achieves the same result, as the solubility of hydrogen in copper is altered. I will retrieve the reference in a while. Plasmic Physics (talk) 02:28, 8 March 2013 (UTC)
It seems that the alloy classification is unnecessary, possibly wrong, and probably misleading for normal chemists. CuH is mainly the ZnS-structured compound made usually by the hypophosphorous acid route. It is rarely obtained pure and like zillions of compounds, there are probably non-stochiometry. Let's just move on. The major sources do not seem to refer to it as an alloy: (Shriver & Atkins, Greenwood & Earnshaw, Well's Structural Inorganic). The crystal structure paper does not refer to it as an alloy. Plasmic we appreciate that you appreciate that binary hydrides are often messy in terms of stoichiometry. Maybe you want to put a single sentence that according to xyz source copper hydride could be classified as an alloy. Just let it go already. --Smokefoot (talk) 13:14, 6 March 2013 (UTC)
This discussion is not about what to call it, even if it is an alloy, it is about the disambiguation of the article. Plasmic Physics (talk) 22:34, 7 March 2013 (UTC)
Plasmic if you are under the impression that chemists call this material a form of metallic hydrogen and that CuH is considered to be anot a real compound, you are in the realm original research. I salute your creativity, but it is the kind of inventive thinking that one publishes in journals not promote within Wikipedia. The material is akin to a saline hydride. It has a crystal structure. Just a normal messy compound, zillions of these things. --Smokefoot (talk) 23:31, 7 March 2013 (UTC)
I'm just calling a spade a spade. Modern research treats it as an alloy in their discussions, without explicit use of the term in reference to the compound. And what is with this sense of patriotism with copper hydride? Plasmic Physics (talk) 00:15, 8 March 2013 (UTC)
The structure of CuH is wurtzite, the copper atoms are therefore hexagonal close packed unlike copper metal which is cubic close packed (fcc). Its not an interstitial- as the copper lattice is different from the metal, cc. palladium hydride. CuH does not show evidence for variable stoichiometry, which would be expected for a true alloy. A recent paper describes it as a copper(I) compound. I wouldn't go that far and just stick with calling copper hydride, the lede could add the words sometimes called an alloy with approriate reference Axiosaurus (talk) 12:27, 8 March 2013 (UTC)
There is no appropriate reference as "copper-hydride alloy" and "copper hydrogen alloy" were used for the first time on Wikipedia. "hydrogen copper alloy" also is unused. So using this name is original research and not appropriate. Graeme Bartlett (talk) 04:36, 9 March 2013 (UTC)
Did I not just say that? Plasmic Physics (talk) 04:57, 9 March 2013 (UTC)
Yes, I am responding to Axiosaurus who suggested that it being called an alloy should be mentioned in the article. It should not. Graeme Bartlett (talk) 09:36, 9 March 2013 (UTC)
As a side, I just found another article that mentions the copper hydride alloy: [1] Plasmic Physics (talk) 10:28, 9 March 2013 (UTC)
This is not about the CuH compounds, but about the limited solution of hydrogen in copper metal, such as 30 parts per million. It does not call it a copper hydride alloy. Perhaps we can accept that as a use of the word alloy, but the red compounds are not alloys. Graeme Bartlett (talk) 12:18, 9 March 2013 (UTC)
The Wurtzite structure is one of the crystallomorphs, as with steel, each crystallomorph is stable at a different hydrogen concentration. At the lowest hydrogen concentration, the substance retains its alpha FCC structure. CuH shows clear evidence of variable stoichiometry. Plasmic Physics (talk) 04:57, 9 March 2013 (UTC)

So why so many primary sources?[edit]

The Wiki guideline is WP:SECONDARY. I worry that the increased emphasis on primary sources violates that advice and leads to WP:UNDUE. Comments? --Smokefoot (talk) 13:02, 10 March 2013 (UTC)

Undoubtedly true. However there doesn't seem to be any secondary literature to cite - I have looked and I can't find any reviews. Considering that copper hydride has no real applications determining what's WP:UNDUE is going to be a problem (actually, it clearly already is). I'm sorry if that's not very helpful but that's the situation as I see it. Project Osprey (talk) 23:52, 10 March 2013 (UTC)
Vindicated! Plasmic Physics (talk) 00:10, 11 March 2013 (UTC)
  • Hardly. It just makes the job harder for all of us, with the likely outcome being deadlock.Project Osprey (talk) 00:23, 11 March 2013 (UTC)
Well, to me it means that Smokefoot has one less thing to complain about. I don't know why, but he has some sort of personal vendeta against me, trying to impede my contributions. Plasmic Physics (talk) 00:48, 11 March 2013 (UTC)
I had cited a couple secondary references - books. Here's the deal. 573 reports exist in Chem Abs on copper hydride. Which of these do you two recommend that we cite? What about this one "Brass dezincification during corrosion with hydrogen depolarization" Burzynska, Lidia in Zeszyty Naukowe Akademii Gorniczo-Hutniczej im. Stanislawa Staszica, Chemia (1990), 1370(15), 11-137.?? Then there is this one "Potential energy function and vertical ionization potential of CuHn (n =, + 1, + 2)" Liu, Yuan; Huang, Ping; Wu, Hai-yan; Ran, Ming Yuanzi Yu Fenzi Wuli Xuebao (2008), 25(1), 79-85. And of course 571 more. So what should we recommend to do?--Smokefoot (talk) 02:45, 11 March 2013 (UTC)
Can I suggest quoting this recent primary source High-pressure synthesis of a new copper hydride from elements, from 2004,Solid State Communications, Volume 131, Issues 3–4, July 2004, Pages 169–173, doi: 10.1016/j.ssc.2004.05.014, where they report a true interstitial "observed at pressure higher than 14.4 GPa. This copper hydride retains the fcc crystal structure of copper. The process of formation of the hydride phase is accompanied by a 7.5% increase of volume of the copper sample." They call this a new copper hydride. (No mention of "alloy" in the abstract.) There is no evidence for the interconversion of this high pressure interstitial with the chimie douce hexagonal form being argued about. This appears to approximate to a Cu(I) compound, see paper "Exploring monovalent copper compounds with oxygen and hydrogen" in this months PNAS, available here I would suggest a new section to describe this new copper hydride phase, which can be called an interstitial alloy. Could I also suggest that the wet hexagonal copper hydride should be noteworthy as the first hydride made, Wurtz A, (1844) On copper hydride (Translated from French) Cr Hebd Acad Sci 18:702–704. and it is also believed to be the only hydride made from aqueous solution. Axiosaurus (talk) 08:54, 11 March 2013 (UTC)
Yes, I did note the last fact, Smokefoot erased it. Plasmic Physics (talk) 12:10, 11 March 2013 (UTC)
I still have my 573 references to insert when we are decided on our policy. We can agree to ignore WP:SECONDARY, WP:UNDUE, WP:RECENTISM as Axiosaurus, Plasmic Physics, and Osprey recommend. How do you propose to proceed?
Personally books are fine provided they have relevent information in them. The 2004 paper I quoted above I cannot find it in a book, if you can, quote that. As a general point relating to wikipedia policy here in the UK web papers are much more accessible than books. Libraries are cutting back, some are being shut. For non-university sraff/students accessing a book other than a high school level text book (dated around 1985 if my local library is anything to go by) is nigh impossible. As for your 573 references I am sure you can increase that! Axiosaurus (talk) 18:42, 11 March 2013 (UTC)


Does copper hydride really form a covalent polymeric solid? A Wurtzite structure would require the hydrides to form 4 covalent bonds, or a 5-center 2-electron bond. Either option seem unlikely to me... but any paper that backs-up a covalent system would would make for interesting reading. Project Osprey (talk) 22:44, 16 June 2013 (UTC)

Highly polarized, hydrogen bridging is involved. Each hydrogen around a copper contributes one quarter of an electron to the copper. Four hydrogens contribute a total of one electron to the copper. Thus, the copper has a net valence of one, if you sum all the partial contributions. Plasmic Physics (talk) 22:55, 16 June 2013 (UTC)
So, yes, it is a 5-centre 2-electron bonding system. Plasmic Physics (talk) 23:37, 16 June 2013 (UTC)
This 2011 paper "Exploring monovalent copper compounds with oxygen and hydrogen" in PNAS, available here; isn't quite as explicit as that. Have you any references for the bonding scheme - the 1995 Fitzsimmons paper was concerned more with the structure- also the comparison with aluminium hydride as another similar hydride is interesting - where did that come from?Axiosaurus (talk) 19:36, 19 June 2013 (UTC)

Copper hydride is a polymer[edit]

If copper hydride is a polymer then shouldn't all solids which are molecular in the vapor state need to be classified as polymers? Axiosaurus (talk) 11:19, 29 August 2013 (UTC)

What's your logic? Have a look at the crystal structure boric acid for a counter example. Plasmic Physics (talk) 11:52, 29 August 2013 (UTC)
Bad example, boric acid dehydrates before melting, try ice instead. Plasmic Physics (talk) 11:56, 29 August 2013 (UTC)
Ice held together by weak hydrogen bonds is indeed a poor example- however many molecular species do form solids with 3 dimensional structures where the bonding is stronger- I was thinking more of say sodium chloride- which exists as a monomer ( as well as dimeric and possibly polymeric species in the vapour phase) but is a (near)ionic solid. Obviously there are quite a few other similar examples. Axiosaurus (talk) 08:05, 5 September 2013 (UTC)
It looks really strange to me, too. Can you give a trustworthy source that says that all or some molecular or ionic solids can be classified as polymers? --Daniele Pugliesi (talk) 22:32, 16 September 2013 (UTC)
Jeesh, I am bewildered by these comments: Binary hydrides for many elements are mostly polymers. Look it up in your textbooks, e,g, Greenwood and Earnshaw. Otherwise the thing would be a gas or mobile liquid, right? Basic stuff. --Smokefoot (talk) 22:52, 16 September 2013 (UTC)
I think you are missing the point. The issue is that this chemical compound has been arbitrarily classified as a polymer not a chemical compound, look at the top of the talk page. Polymer in the context of wikipedia projects does not include all molecular species that aggregate to form non discrete molecular solids. The bonding in CuH is not known, is it a covalent polymer like alumane with multicentre H bonds or does it include Cu-Cu bonding as suggested by its color, it needs references. And by the way, basic stuff, metal hydrides are usually salt like or interstitial. A transition metal binary hydride which is a covalent polymer would possibly be a first. Axiosaurus (talk) 07:50, 17 September 2013 (UTC)
'Polymer' and 'chemical/compound' are not mutually exclusive. Moreover, I do believe that the PolymerProject is a daughter project of the ChemicalProject.
Why does its colour indicate Cu-Cu bonding? Basic stuff? metal hydrides are certainly not usually salt like or interstitial, excluding the alkali metal hydrides and most alkaline earth hydrides. Plasmic Physics (talk) 08:22, 17 September 2013 (UTC)
FYI many copper(I) compounds are colorless, such as copper(I) chloride. The Cu-Cu distance in the wurtzite structure of CuH is around 290 pm, Cu-Cu in metal around 256pm, metallic copper is colored this suggests (not indicates!) metal-metal interaction. Regarding transition metal hydrides called interstitials/ intermetallics there are a lot of them, non-stoichiometry is the rule. Have a look at this paper describing bonding in TiH2 Solid State Communications, Volume 41, Issue 6, February 1982, Pages 491–494. A conducting solid rationalised in terms of metallic interaction. Wth CuH there is a problem, there is a structure, it is colored, its electrical properties are not known, presumably samples are too contaminated. As a covalently polymerised transition metal hydride without metal-metal interactions it would be unusual perhaps unique. Personally I hope it is, that would really stir things up. However hope can't be referenced. Axiosaurus (talk) 10:08, 17 September 2013 (UTC)
There are also a few cuprous compounds which are coloured, such as copper(I) oxide (which is also red and polar covalent). Interstitials and intermetallics aren't compounds, but alloys. I practically wrote Titanium hydride, so there is an example. Plasmic Physics (talk) 10:38, 17 September 2013 (UTC)
Sorry, I didnt catch that the debate was polymer vs compound. Sometimes this is a distinction with little difference, at least for inorganic materials. Rather than calling it a polymer, perhaps polymeric would be better. Not sure what the color is supposed to say about bonding. Cu6H6(PPh3)6 is dark red. Few (none?) compounds exist with unsupported (i.e., unbridged) Cu-Cu bonds. The aspect that would worry experts is the reference to "molecular copper hydride". The article has a characteristic fetish-like slant to it that even experts dare not edit here nor in related articles. --Smokefoot (talk) 12:55, 17 September 2013 (UTC)
What is the problem with "molecular copper hydride"? Plasmic Physics (talk) 13:08, 17 September 2013 (UTC)

Stryker's reagent[edit]

The content on Stryker's reagent might be relocated to that article. Related ideas: emphasis taken off of the PI's who ran the research groups, and references refocused on WP:SECONDARY references. A lot of the article is a fringe perspective and probably should be contracted one of these days. --Smokefoot (talk) 12:27, 18 June 2016 (UTC)



Copper hydride can assimilate a hydroxyl centre into the molecule by ionisation:

   CuH + OH− → CuO− + H2

Because of this capture of the hydroxide (OH−), copper hydride has an acidic character. Its hydroxylation product is oxocuprate(1−). Copper hydride does not form aqueous solutions, due to it being a covalent network solid; however, it does form colloidal suspensions. It is also oxidised by water, albeit slowly.

End quote

This appears to be a fundamental misunderstanding of chemistry principles. The example shows that CuH is a hydride source, behaving as "H-" and abstracting "H+" from OH- to form H2 and the equivalent of "O[2-]". Of course, no O[2-] actually forms since ligation to Cu(I) should be extremely favorable, and the process presumably proceeds by sigma-bond metathesis in a concerted manner.

Irrespective of the actual mechanism, it is certainly wrong to call CuH an acid. If anything, CuH is a base in the Bronsted-Lowry sense, while it may be considered an acid-base adduct (Cu+ acid, H- base) in the Lewis sense. I am deleting this entire section, which is not particularly well written in any case. Ymwang42 (talk) 05:59, 18 June 2016 (UTC)

It is good you have removed this. The same kind of original research has been added to many hydride article. You will note no supporting reference! Graeme Bartlett (talk) 12:25, 18 June 2016 (UTC)
Thanks from me too. As Graeme indicates, you are encouraged to examine other hydride articles. --Smokefoot (talk) 16:00, 18 June 2016 (UTC)