Talk:Hydride

Contradiction

This article contradicts itself. It begins by defining a hydride as a compound of hydrogen with more electropositive elements. It later lists ammonia and water (amongst others) as hydrides, yet these are compounds of hydrogen with more electronegative elements.

As far as Greenwood and Earnshaw is concerned, hydrides are all the binary compounds of hydrogen with another element, of the general form A_xH_y. I think the introduction of this article should be rewritten accordingly.

Ben 20:38, 22 December 2006 (UTC)

How a binary hydride be of the form A_xH_y when hydrogen has valence 1? The formula of such a compound is AH_x. Explain if this is incorrect. --HtnbdResuf (talk) 16:12, 31 August 2009 (UTC)

Lots of covalent compounds have A_xH_y stoichiometries. An example is hydrogen peroxide, H₂O₂. This molecular formula could in principle be simplified to the empirical formula HO (conforming to the AH_x definition) but is misleading since this normally represents a hydroxyl radical.

Another example is decaborane, B₁₀H₁₄. The presence of A-A bonds allows the formula to deviate from AH_x.

You can also have non-stoichometric hydrides, such as palladium hydride, PdH_0.02 to PdH_0.58.

You can put AH_x if you allow x not to be an integer.

Ben (talk) 17:06, 31 August 2009 (UTC)

Suggestion

Hydride is the name give to the negative ion of hydrogen, H⁻. It is also used as a more general term to describe compounds of hydrogen with other elements, particularly those of groups 1–16, whether or not they actually contain hydride ions. Protide, deuteride and tritide are used in the same way to describe ions or compounds which contain enriched hydrogen-1, deuterium or tritium respectively.

Physchim62 (talk) 02:09, 23 December 2006 (UTC)

Definition

According to my dictionary, a hydride is a binary compound formed by hydrogen and another, usually more electropositive, element or group, as sodium hydride, NaH, or methyl hydride.... Moreover, that definition is more in keeping with the use of the word in the article itself, as well as in articles linking to this one. Why not state so outright, instead of saying it's "applied to describe" them, while being "the name given to" something else entirely -- "the negative ion of hydrogen"? Referring to "hydride" as a thing or substance conflicts semantically with discussing the hydrides as a family, a concept which probably predates the use of the word to refer to an ion. D021317c (talk) 13:22, 20 November 2007 (UTC)

Oh your comments are appropriate, but the chemistry community/tradition does not always follow the rules of dictionaries. And we would all like to state the situation "outright" as you say, but term hydride is used more subtly. Hydride refers to hydrogen atoms that are fairly basic (resulting from their attachment to electropositive elements or groups) but methyl-H is not hydridic, usually. I wished that the chemical word and the world of nomenclature were more perfectly alligned, but they are not and this and other articles defers to reality in the flask vs the rules of language. At least that's my view.--Smokefoot (talk) 13:42, 20 November 2007 (UTC)

Then explain both worlds explicitly. The usage may be subtle, but the article doesn't need to be confusing. 89.217.12.82 (talk) 18:21, 28 January 2015 (UTC)

@D021317c and Smokefoot: I come to this section with the same question. In PowerPoint slides of Zumdahl 8th edition (and perhaps the book), water is regarded as one of the covalent hydrides. LibreTexts also discusses ammonia/hydrogen halides as examples of covalent hydrides. However, the article has this line According to the convention above, the following are "hydrogen compounds" and not "hydrides":[citation needed]. I think it is ok to explain both views as long as we have proper citations. I can get a quick look into several general chemistry textbooks and revise to line. --Taweetham (talk) 01:11, 24 June 2020 (UTC)

Commons category... Ionic hydrides

From google[1] (and a mere 405,000 hits), per the above category link:
   "The collection of instances of chemical compound formed when hydrogen reacts with any of the Alkali Metal Elements, calcium, strontium, or barium.[2]"

... which matches nothing categorized therein. Though [ http://www.experiencefestival.com/a/Hydride_-_Ionic_hydrides/id/5290965 this coverage] seems far more likely to my 35 years ago chemistry...

And in slides 8 through ten of: http://www.lyon.edu/webdata/users/fbeckford/CHM%20120/Lecture%20Notes/Chapter-14.ppt which also covers the term Molecular hydrides, which is another null search[3] in our pages. (And I hate that! <g>)

Can someone update the article with some coverage of these and place an explanation blurb in the commons category as well. You really don't want me editing chemistry articles! Trust me! <g> Thanks // FrankB 03:59, 28 July 2008 (UTC)

• Add in the deficiency in the article that the redirected term and category Metal hydride is not covered and visible in the introduction... I surmise from cited edits at Lithium hydride and Sodium hydride that this may be and is likely a synonym of ionic hydride. // FrankB 04:49, 28 July 2008 (UTC)

• Add in request for Covalent hydrides article

4-5 cites hidden here!

http://www.google.com/search?q=Covalent+hydrides&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

Britannica online encyclopedia article on chemical compound, Covalent hydrides: The covalent hydrides are primarily compounds of hydrogen and nonmetals. http://www.britannica.com/eb/article-79480/chemical-compound

"Britannica Concise Encyclopedia: hydride via answers.com". Retrieved 2008-07-28. Covalent hydrides (see covalent bond) are mostly compounds of hydrogen and nonmetallic elements; they include water, ammonia, hydrogen sulfide (H2S), and methane. A fourth group of hydrides, dimeric (polymeric) hydrides, is sometimes recognized (see borane). Dimeric hydrides give off large amounts of energy when burned and may be useful as rocket fuels. [http://www.nature.com/nature/journal/v178/n4537/abs/178808a0.html Free Radical Reactions with Inorganic Covalent Hydrides: a Route to Polyfluoroalkyl Silicon Compounds]

Dependence of bond angles on overlap integrals form some covalent hydrides, D.A. Hutchinson, University of Victoria

Solid-state structures of the covalent hydrides germane and stannane, I. J. Maley, D. H. Brown, R. M. Ibberson and C. R. Pulham

• • Note, just noticed Covalent hydride redirects to a section... which was not heralded in the introduction per WP:MOS guidelines... and is rather skimpy as well, given the differences between that section and the hidden cites/links. // FrankB 05:40, 28 July 2008 (UTC)

Its easy to tag technical article and to google information, good and bad, but your point is what?--Smokefoot (talk) 13:02, 28 July 2008 (UTC)

Citations

It would be nice to get some citations for this article. Lets cite this article and/or rewrite it to reflect the practical usage of the term hydrides. We should also clearly explain that the antiquated hydride nomenclature in which almost anything that has hydrogen in it can be refereed to as a hydride is very antiquated.--OMCV (talk) 04:01, 28 April 2009 (UTC)

Free Protons

I had removed the claim that free protons only exits in extreme conditions because it is flat-out wrong. Go read up on pH FMI there. Someone else added it back in, saying that free protons can only exist in rare circumstances due to a "high charge/radius ratio." Again, I'm pretty sure this is flat-out wrong. Free protons are just dissolved H+ ions, and they occur all over the place (small amounts of water spontaneously break up into H+ and OH- ions, as do all acids which by definition break into H+ and some sort of negative ion whose composition depends on the acid). There are no issues of high charge buildup due to free protons because they are accompanied by negative ions and the total charge remains neutral. If you have a source that describes free protons as being rare, feel free to add in a citation. In the meantime, I'm going to remove the part about free protons being rare and replace it with a mention of pH and free protons being common in acids. and since this whole thing is off-topic, I intend to remove all mention of free protons in a few months if there are no complaints. —Preceding unsigned comment added by 75.85.86.139 (talk) 23:37, 19 December 2009 (UTC)

What you have in acidic solutions are not truly free protons - they are solvated. In aqueous solution, chemists often consider the solvated hydrogen ion to exist as H₃O⁺, but this itself is a simplification. See Grotthuss mechanism and Hydrogen ion for details.

Ben (talk) 01:07, 20 December 2009 (UTC)

Thanks Ben I think your explanation pretty much covers it. Suffice it to say that the proton is a lot more complex than the way its presented in most general chemistry classes.--OMCV (talk) 01:21, 20 December 2009 (UTC)

iron hydride

Does it exists? --RokerHRO (talk) 09:31, 19 May 2011 (UTC)

under pressures of over 3.5GPa a hexagonal iron hydride exists.[4] FeH is also an important molecule in stars. Graeme Bartlett (talk) 12:07, 18 April 2012 (UTC)

Revisions of Oct 17, 2011

I made a number of bold revisions of this article. Feel free to make constructive criticisms or voice concerns and I will try to address issues. Here are the main points. Transition metal hydrides are not really a class of hydrides (like saline, covalent, interstitial). The statement was made that the nonexistence of hydrides in solution (water, really) is akin to the non-existence of protons in water. While it is true that naked protons do not exist, solvated protons do. There is not an analogous solvated hydride, at least I dont know of such species. The nomenclature section seems long and somewhat arbitrary, but other articles accumulate such lists. The problem with such lists is that they obscure the readability and they are arbitrary. IMHO, categories are a better kind of list. I also tried to minimize the number of sections by blending similar topics. I will check back tomorrow.--Smokefoot (talk) 13:56, 17 October 2011 (UTC)

"battery hydrides"

The technically very important alloys used for hydrogen storage in NiMH batteries seem to have been left out. They probably belong to the interstitial hydride group. There is some, but rather little, information on this in other articles (eg on the batteries or on Lanthanum) but I can't find any article on the alloys per se or the most important group of these alloys, the AB5 group. — Preceding unsigned comment added by 150.227.15.253 (talk) 10:11, 29 November 2011 (UTC)

Metal Hydride heat engine - hoax?

The web (especially YouTube) is full of "Metal Hydride" heat engine info. Is this a hoax? If not, it should be mentioned in the "uses" section.

The claim is that "Metal carbide" supposedly expands drastically, "without condensing on the piston", when in contact with heat. Can someone confirm? פשוט pashute ♫ (talk) 08:16, 18 April 2012 (UTC)

It seems the only way to get a response from people about this is to add it in the main article, and then get "flamed". I'll try and lets see what happens. פשוט pashute ♫ (talk) 14:40, 15 November 2012 (UTC)

It is not a hoax. See https://doi.org/10.1016/0013-7480(79)90016-0 or https://patents.google.com/patent/US5082048. But it would not be a "use", as it is just a demonstration or invention. Graeme Bartlett (talk) 07:23, 12 May 2020 (UTC)

Antiquated definition

The article says:

"Covalent hydrides According to the antiquated definition of hydride covalent hydrides cover all other compounds containing hydrogen. The more contemporary definition limits hydrides to hydrogen atoms that formally react as hydrides and hydrogen atoms bound to metal centers. ".

So apart from spelling centre wrong (national variation I guess), a hydride is something which behaves like a hydride? Not much of a definition. The wording 'antiquated' immediately strikes me as POV. Some of the discussion on this page suggests it is not so antiquated a definition in that a number of quietly rusting scientists still seem to hold it (like me). Wiki reports what is, not what people would like to be and if many hold a view, thats what is. I dare say the article is correct in suggesting that a tighter definition of hydrides has been created in contemporary chemistry, redefinition is a typical trend in science, but I dont know this. The current wording seems to be having a bit of a dig at incompetent ancients. Sandpiper (talk) 07:48, 7 August 2012 (UTC)

RE: "a hydride is something which behaves like a hydride? Not much of a definition." - it uses the wording "formally react as...". It does this to allow molecules which would not otherwise be classed as hydride because either they react in a mechanism that is not the hydride mechanism (but produces the same result) or a similar exception. 83.70.170.48 (talk) 11:31, 6 September 2012 (UTC)

Merger proposal

I propose that Binary compounds of hydrogen be merged into Hydride. I think that the content in the Binary compounds of hydrogen article can easily be explained in the context of Hydride, and the Hydride article is of a reasonable size that the merging of Binary compounds of hydrogen will not cause any problems as far as article size or undue weight is concerned. Plasmic Physics (talk) 12:19, 9 August 2012 (UTC)

• opposed, Binary compounds of hydrogen is the first in what should become a large series of articles, binary compounds of silicon is the next. The scope of these articles will be too technical for a general interest article such as hydride. V8rik (talk) 18:00, 9 August 2012 (UTC)
• oppose - splits like this extend Wikipedia, some like hydrocarbon or silanes may be well developed and interstitial hydride underdeveloped, but it does not matter if there is overlap as only the readers who want a more technical knowlege will click deeper. We don't want everything in the hydride article, although some things like the periodic table of hydrides could be in here too. Graeme Bartlett (talk) 13:04, 10 August 2012 (UTC)
• support. Although well intentioned, making lists risks becoming WP:SYNTHESIS, IMHO. The problem is greatest especially for a class of compounds so broad and filled with so many poorly defined (non stoichiometric) members. And editors will no doubt want to speculate/pontificate and pass comment on the tentative assignments, which is also risky business. But then writing any article has such risk and, as others have reminded us, there is no limit to the number of words in WIkipedia. --Smokefoot (talk) 13:19, 10 August 2012 (UTC)
• Currently the existence of three articles about the negative oxidation state of hydrogen looks quite confusing. If hydrogen anion does not appear in chemical context, and is not expected to exist in any compound, then "hydride" actually means nothing but a covalently-bound compound of hydrogen, right? FYI I am not an expert. Incnis Mrsi (talk) 06:52, 22 August 2012 (UTC)
• Support - Currently all binary-hydrogen molecules are Hydrides. While silicon may use different naming convention, there is already an article featuring hydrides.83.70.170.48 (talk) 11:27, 6 September 2012 (UTC)

• Difficult, I would consider Hydride to talk about the hydride-ion, H^-. Binary compounds of hydrogen may be extensive enough for an own article. However, Carbide exists and Binary compounds of carbon do not. Should Carbide talk about 'C^4-' and Binary compounds of carbon about the compounds? I do feel that both are two distinctly different compounds, and maybe for hydride the case can be made that they need to be separate (but clearly point to each other 'you may be looking for binary compounds of hydrogen', and 'you may be looking for hydride'), whereas for carbon there is not enough (and binary compounds of carbon should simply be an explained redirect). I would note that for these articles to exist, that there needs to be enough notable information to warrant that section (binary compounds of berkelium is not likely going to have more than 1 'notable' example, which in itself may hardly be notable enough to warrant the mention of binary compounds of berkelium). I would tend to (albeit weakly) oppose merging at this point, though this does not necessarily set a precedent for other articles. --Dirk Beetstra ^{T C} 13:58, 24 September 2012 (UTC)

• Strongly oppose - My opposition is not one on principle, (the idea of an over-arching article pointing to detailed articles is appealing), but is based on the relative quality of the two articles. In my view the Binary compounds of hydrogen article is of much lower quality than the hydride article. I found it confusing, inaccurate in places and poorly referenced. Hydride in comparison is a better article. Sort out the binary compounds article first and then come back with a merge proposal would be my advice. Axiosaurus (talk) 07:08, 19 September 2013 (UTC)
  • interesting comparison regarding references: I am counting three general textbook references in the hydride article (not counting the ones on highly specialistic topics) and 4 in the binary compounds of hydrogen article. Which one of the two was poorly referenced? The bit on non-classical hydrides is a more recent contribution lacking context is indeed non-referenced. V8rik (talk) 19:08, 19 September 2013 (UTC)

You are right there are more references to general text books in binary compounds than in the hydride article. However those in binary compounds are inline and against the same statement in the lede. The current article bears little relation to the version you left and has moved in a different direction and therefore the contents cannot be said to be adequately referenced by those general text books, in fact in places it flatly contradicts them. Axiosaurus (talk) 14:08, 20 September 2013 (UTC)

• Seeing as this is still going, strongly oppose on the basis that H₂O, CH₄ and HF should never be considered hydrides any realistic chemical sense. Tomásdearg92 (talk) 16:56, 29 November 2015 (UTC)

Reassessed as C Class

The overall quality of the article has reduced since the last assessment.Axiosaurus (talk) 10:45, 24 October 2013 (UTC)

mixed anion compounds

@Gah4: you removed my recent redlink addition for several mixed anion compounds. Some of these were not redlinks, and the others I am drafting. The topics are all notable. Graeme Bartlett (talk) 11:36, 18 May 2020 (UTC)

Write the articles, and then link them. If they are notable, others will figure that out. I started article about color developing agents, without which we would not have color photography, but some are claiming that they are not notable. You can discuss here why they are notable, or write the articles and discuss them. Probably easier to discuss here, and now. Gah4 (talk) 15:53, 18 May 2020 (UTC)

Thanks for getting the articles before linking. Personally, I don't believe that they are notable, but it is far from my specialties. (Some years ago, I did work with LiAlH4, but that is as close as I got.) Now someone else will get to figure out the notability. Just wondering, how did you get interested in these? Some years ago, I was trying to figure out how to electroplate aluminum, though never got it to work. Gah4 (talk) 01:50, 20 May 2020 (UTC)

Elements without hydrides

I rather suspect Fr and Ra are rather cases of "no one tried due to radioactivity". Judging from Cs and Ba they probably could if anyone tried. Double sharp (talk) 11:43, 24 June 2020 (UTC)

The longest Francium isotope has a 22 minute half life. You would have to be fast to make FrH, and I don't see much reason to put it on the list. Ra has long enough half life, though, so maybe there is another reason. Gah4 (talk) 16:03, 24 June 2020 (UTC)

I rather doubt it: "we can assume that the properties of these hydrides would be similar to those of the other alkali and alkaline-earth metals" (Metal Hydrides, edited by Mueller, Blackledge, and Libowitz, p. 165). Radium and barium usually act very similarly and I can't think of any reason why they wouldn't in this case. Double sharp (talk) 12:26, 25 June 2020 (UTC)

I doubt it, too, but not enough to say to remove it. It is much more obvious for alkali metals, which really want to get rid of that electron. Gah4 (talk) 13:05, 25 June 2020 (UTC)

Well, I did give a source here saying that it should be expected of Fr and Ra, so we may justify it in a note. Promethium also seems to be this kind of exclusion, judging from how every other lanthanide has a known hydride. In any case it seems to me that there is at least a conflation of elements that genuinely have no strong interest in forming a neutral hydride (e.g. helium) and those for which there is simply absence of evidence rather than evidence of absence (e.g. francium). The latter is an annoying problem when writing about the rare radioactives (already Po is quite spottily documented, it only gets worse, especially since radium does not seem to be used for much anymore). Double sharp (talk) 13:32, 25 June 2020 (UTC)

In that case... I was going to go for WP:OBVIOUS for Fr but not Ra. Gah4 (talk) 14:09, 25 June 2020 (UTC)

What about technetium (the ion ${\ce {TcH_9^{2-}}}$ exists, but what about neutral hydrides?), xenon, and transcalifornium elements? Burzuchius (talk) 16:37, 1 July 2020 (UTC)

Seems to me that it counts. Gah4 (talk) 19:42, 1 July 2020 (UTC)