Talk:Iron–hydrogen alloy

Stoichometry and fourth form

If I understood correctly, Antonov et al conjectures that one of the high pressure forms is FeH
_0.42 or so rather than FeH, and that there is a fourth metastable form. But I could find no confirmation of either. --Jorge Stolfi (talk) 18:06, 18 February 2013 (UTC)

Confusion

I am confused. Iron-hydrogen cannot be both an alloy and a chemical compound, iron hydride. Biscuittin (talk) 01:04, 30 November 2014 (UTC)

No, you are incorrect. An alloy is, by definition a mixture, either a compound or a solution, of (at least) one metal (metallic element) and at least one other element of which the resulting "mixture" has some characteristics of a metal. (That's pretty vague and not particularly helpful, but it is what it is.) There's no obvious reason a compound (whether stoichiometric or not) of iron can't be an alloy. The article states quite clearly that H is present at ~13 ppm in the alloy - pretty obviously* way below what could be a chemical hydride. What I am saying is that the chemical compounds of Fe and H are not alloys, and the alloy of Fe and H isn't a compound but apparently both are named Iron Hydride (It is a name that I'd bet isn't approved by IUPAC, but I don't think they deal with alloy names, so their conventions likely aren't applicable (for the alloy).) *Pure iron at stp exists with either a bcc or fcc crystal structure. The bcc structure has two "atoms" per unit cell, fcc has 4. So, a reasonable assumption would be that at the least, H will be present in iron hydride (pure compound) with a stoichiometry Fe₄H. This works about to be about 4500 ppm H and two orders of magnitude above the 13 ppm of the alloy.72.16.97.19 (talk) 21:55, 18 May 2024 (UTC)

Who said that it is a chemical compound? Plasmic Physics (talk) 12:00, 30 November 2014 (UTC)

The first line in the article: "Iron–hydrogen alloy, also known as iron hydride". Iron hydride is a compound and has a fixed formula. Alloys have variable formulae. Biscuittin (talk) 16:42, 30 November 2014 (UTC)

The article you link to does not refer to a single compound as you suggest, and correctly states that the term has more than one meaning. In this usage, it refers to the alloy. Plasmic Physics (talk) 20:17, 30 November 2014 (UTC)

Use Palladium as example. To separate 2 Hydrogen atoms, the H2 molecule, take 104 Kcal/mole. Thats why air and hydrogen mixtures don't react without heat or spark. Hydrogen is split on Palladium surface with Hydrogen-Hydrogen bonds are now Palladium-Hydrogen connections. Pressure up to PdH1.7 after not enough Pd cohesion and powdered PdH2 forms. Note the huge difference in size between Pd and H? Small enough to fit between Pd atoms. Metals have some orbitals unified into metallic states that allow electrical conduction. If Hydrogen shares its electron when metal it joins the metal as an alloy (think alloy) and remaining Hydrogen nucleus, tiny and shielded has high mobility in the Pd. In fact Palladium discs (5% Silver to prevent PdH2 forming) are used to purify Hydrogen by Hydrogen flowing through the solid disc. TaylorLeem (talk) 19:38, 31 August 2020 (UTC)

Accuracy dispute

Quote: "The hydrogen in typical iron hydride may contribute up to 0.001% of its weight". Iron(I) hydride contains 1.75% hydrogen and Iron(II) hydride contains 1.72% hydrogen. The author seems to be using Iron hydride as a synonym for Iron–hydrogen alloy when it is actually something completely different. Biscuittin (talk) 17:03, 30 November 2014 (UTC)

The reference I gave, exemplifies how 'iron hydride' is used to refer to the alloy. Plasmic Physics (talk) 20:19, 30 November 2014 (UTC)

The on-line reference only mentions Iron hydride. It does not say that Iron–hydrogen alloy is a synonym. Biscuittin (talk) 20:27, 30 November 2014 (UTC)

Even though, it is not explicitly using the term 'iron-hydrogen alloy', we already know that it is using 'iron hydride' to refer to the alloy. Plasmic Physics (talk) 22:11, 30 November 2014 (UTC)

How do we know? Biscuittin (talk) 22:43, 30 November 2014 (UTC)

It is called an alloy, and treated as such elsewhere. Plasmic Physics (talk) 22:54, 30 November 2014 (UTC)

Where? Biscuittin (talk) 23:02, 30 November 2014 (UTC)

I have amended the article, to remove the confusion. If you are happy with this, I think the accuracy dispute is settled. Biscuittin (talk) 10:14, 1 December 2014 (UTC)

First of all, the statement fragment "The term may refer to iron with a very low percentage of hydrogen..." repeats what is in the paragraph immediately following. The fragment "...absorbed in the molten state at ordinary pressures..." is incorrect in terms of its exclusivity - absorption is not limited to the molten state. Secondly, the high pressure forms are not compounds. Plasmic Physics (talk) 11:39, 1 December 2014 (UTC)

OK, I have changed "also known as iron hydride" to "sometimes known as iron hydride". Is this acceptable? My point is that Iron–hydrogen alloy and Iron hydride are not the same thing. Biscuittin (talk) 13:46, 1 December 2014 (UTC)

Why are you insisting that is the case, when there is an entire article that serves the sole purpose of saying that 'iron hydride' is in fact a synonym for iron-hydrogen alloy among several other meanings? Plasmic Physics (talk) 21:35, 1 December 2014 (UTC)

I'm not sure whether you are agreeing with me or disagreeing with me. Could you please try to clarify your last statement. Biscuittin (talk) 00:59, 2 December 2014 (UTC)

I'm saying that I'm frustrated with my inability to correct your understanding of the term 'iron hydride'. I'm saying the page Iron hydride is a set index article, describing the different usages of the term, including as this alloy. I can't figure out whether you're just ignoring it, or haven't bothered to actually read through the article. Plasmic Physics (talk) 01:47, 2 December 2014 (UTC)

Have you resolved this dispute or do you still need a third party to look over the situation? Tarnas (talk) 05:23, 2 December 2014 (UTC)

Yes please, we do need a third party. User:Plasmic Physics and I seem to be totally unable to understand each other. Biscuittin (talk) 09:43, 2 December 2014 (UTC)

I have restored the article to the version by Plasmic Physics dated 1 Dec 2014 and added a top link for clarification. However, I still think the article is misleading because it uses the terms "Iron–hydrogen alloy" and "Iron hydride" as if they were interchangeable. It may be that physicists call Iron–hydrogen alloy Iron hydride but, to a chemist, this is wrong because one is an alloy and the other is a chemical compound. Biscuittin (talk) 13:48, 2 December 2014 (UTC)

I reject the idea that Iron hydride is a set index article. A set index article (e.g. Copper oxide) is just a list. Iron hydride is an article with references. Biscuittin (talk) 14:03, 2 December 2014 (UTC)

Perhaps I am out of date. I have just read Interstitial compound and it seems that a compound can be an alloy. Biscuittin (talk) 14:12, 2 December 2014 (UTC)

I see that User:Plasmic Physics has edited Iron hydride to match his point of view without giving a reference. Biscuittin (talk) 14:22, 2 December 2014 (UTC)

It does not matter if it's right to a physicist and wrong to a chemist, Wikipedia is for everybody. There is no credible reason to discriminate against an established synonym other than practical ones. A set index article is more than just a list copper oxide is a poor example. The prime example given in the article which directed you to, is Dodge Charger. The reason for the expanded definition in iron hydride, is to take account of the definition of the difference between compounds and mixtures as stated in Chemical compound#Compounds compared to mixtures Plasmic Physics (talk) 01:32, 3 December 2014 (UTC)

I've reviewed your situation and the related topics. I'll be back in a few hours to start the discussion and give you my perspective. Tarnas (talk) 21:38, 2 December 2014 (UTC)

From what I can tell, there are two major things going on here. (#1) User:Plasmic Physics is a domain specialist who contributes a lot of content to a variety of articles, but he does not appear to be particularly good at citing sources for his contributions. This is problematic because, though what he writes appears to be correct, without a source no one can check. However, since this is a low priority chemistry page dealing with an esoteric subject, I would err on the side of leaving User:Plasmic Physics's contributions. User:Plasmic Physics, it would help if you could be more diligent in citing sources. If you are inspired to expand articles rapidly in the way that appears to be your M.O. based on your contribution history, you should perhaps create drafts beforehand and carefully find citations to your statements. This is time-consuming work but wikipedia users in the years ahead will be thankful, and there's no other way to ensure that all your work stays put unless it's cited. Other users can leave uncited scientific material in an article only so long before someone needs to find a citation or delete it.

(#2) The beginning of this dispute, however, is a much more narrow question: the difference between alloys and compounds. In the case of metal solutions with less massive elements like hydrogen, there is no clear line between mixtures, alloys, and compounds. This is not the neat world of chemistry that we were perhaps taught in school. It is now very much the domain of specialists. It appears that chemists are themselves rather lax in using the term "alloy". Perhaps a more accurate approach for defining these substances is to refer to "phases". Here are some related documents on the subject:

• Phase_(matter)
• Solid_solution
• Bonding_in_solids
• Metallic_bonding
• Intermetallic
• Transition_metal_hydride
• Non-stoichiometric_compound

If I had lots of time to deal with this, I would probably recommend merging Iron–hydrogen_alloy into Iron hydride (it appears to have been split off by a non-chemist some time ago) and giving every phase, compound, alloy, or whatever you want to call it of the iron-hydrogen system its own due treatment. It would probably be best to create a single chart of all possible iron-hydrogen systems, with phase diagrams, and give any secondary technical names for specific phases, so that all of them can be seen in one place. I am not going to do this though, and I would recommend simply noting in this article that there is no strict definition of the term "alloy" in the context of metal hydrides; that it may be more for historical or industrial reference purposes that the nomenclature persists; and ideally we would find a discussion of this issue in a citable textbook, chemical naming specification, or other source, and use that to inform this article. But really the overlap between alloys, compounds, solid solutions, phases etc is a larger problem in this area of chemistry and physics and won't be solved in this minor article. User:Biscuittin, it appears that if you want clarity, you will also have to go to the scientific literature and find a discussion of the use of the term "alloy" among metal hydrides, and distil that discussion for wikipedia.

I'm not sure where that leaves us but I'll stop writing now and see what you each have to say.Tarnas (talk) 03:54, 3 December 2014 (UTC)

The technical issues are clearly more complex than I thought so I do not intend to make any more edits to Iron–hydrogen alloy at present. However, I think the article needs to be examined by an expert because the accuracy of recent edits cannot be confirmed without references. Biscuittin (talk) 13:24, 3 December 2014 (UTC)

I see there has been an earlier discussion about iron hydride at User_talk:Plasmic_Physics/Archive_5#Iron.28I.29_hydride which might be relevant to the current discussion. Biscuittin (talk) 16:58, 3 December 2014 (UTC)

Editing proposal

Nearly all the contributions from User:Plasmic Physics have been unreferenced and, in some cases, inaccurate. As an example of inaccuracy I give this: "Iron is extracted from iron ore by removing the oxygen through combination with a preferred chemical partner, such as hydrogen that is lost to the atmosphere as water". Unless I am much mistaken, the usual way to extract iron is by reducing iron ore with carbon, see Iron_ore#Smelting. Because of this, I intend to restore Iron–hydrogen alloy to the version of 31 August 2014 by 88.104.104.115. I am putting this up for discussion before I do it. Biscuittin (talk) 20:47, 2 December 2014 (UTC)

I would recommend waiting for a few days until we consider the pending dispute above. It's quite possible that User:Plasmic Physics is contributing useful information but is not good at citing sources, and this wikipedia article is of low enough priority that there is no need to revert it immediately. Tarnas (talk) 21:36, 2 December 2014 (UTC)

OK. Biscuittin (talk) 23:07, 2 December 2014 (UTC)

The sentence makes no indication whatsoever that the extraction process is the preferred method. Plasmic Physics (talk) 01:41, 3 December 2014 (UTC)

Earlier I disagreed with Plasmic about calling solid hydride compounds "alloys". There seemed to be original research and undue pushing of the term. He did find one reference that suggested the use alloy, but primarily "alloy" was not used. The original article called iron hydride that I wrote was about all the different iron hydrides, including the molecules, the high pressure phases, (with different crystal structure) and the low pressure, low hydrogen composition substance (that last could be termed an alloy as it had the same crystal structure as pure iron). Graeme Bartlett (talk) 01:27, 3 December 2014 (UTC)

Who says that is a requirement for any alloy? Plasmic Physics (talk) 01:41, 3 December 2014 (UTC)

At least three sources referring to it explicitly as an alloy: [1],[2], [3]. Plasmic Physics (talk) 01:50, 3 December 2014 (UTC)

I am saying that we had an argument about it. But I have not said what I think needs to be changed. This article is about solid or liquid iron hydride. It is not a set index, but a stlightly more general article documenting condensed forms. It is rarely called an alloy, and very seldomly called "iron hydrogen alloy". But that is not what the dispute is about. Most of the content here is what I originally wrote, but what is different is the lede and the section on the low % H alloy. Graeme Bartlett (talk) 03:14, 3 December 2014 (UTC)

Looking at the references above, the first I can't tell, the second uses the term "iron hydride", but the last does use the term "iron hydrogen alloy" with no dash or hyphen. So nothing matches the current article title. Graeme Bartlett (talk) 03:20, 3 December 2014 (UTC)

I did not say that this article is an SIA, but instead the article, Iron hydride is. Yes, those sections are different, but that is not what the dispute is about either. The dispute is about whether term "iron hydride" is an acceptable synonym, and whether there is any clear-cut distinction between low hydrogen, and high hydrogen, Fe-H systems. I'm relaying that it is an acceptable synonym, since there are available source; and that there is no clear-cut distinction, since both those systems exist concurrently in different zones within the 3D (composition-temperature-pressure) phase diagram. Plasmic Physics (talk) 04:51, 3 December 2014 (UTC)

I agree that the term can be a synonym. There is also a clear cut distinction between the low hydrogen and high hydrogen forms, as they have different crystal structures, with hydrogen at different positions. The high hydrogen form has a definate maximum hydrogen where all occupations sites are used. Low hydrogen forms are just alloys with hydrogen as a minor component. Graeme Bartlett (talk) 07:23, 3 December 2014 (UTC)

The austenitic form (FCC) is common to both the low and high forms. The low hydrogen forms also have maximum solubility for the same reason, albeit much less stable. Plasmic Physics (talk) 08:47, 3 December 2014 (UTC)

Continued confusion

I'm not blaming User:Plasmic Physics for this, because the article was not created by him, but the article is still confusing. Its title is Iron–hydrogen alloy but, throughout the article, the substance is referred to as Iron hydride. If the article is about Iron–hydrogen alloy, it should be referred to as Iron–hydrogen alloy. The statement "The hydrogen in typical iron hydride may contribute up to 0.001% of its weight" is particularly misleading because iron hydride, as a compound, contains a lot more hydrogen than this. Biscuittin (talk) 13:11, 5 December 2014 (UTC)

I think one possible solution might be to re-name the article Properties of iron hydride at high temperature and pressure. Biscuittin (talk) 13:16, 5 December 2014 (UTC)

That statement relates to iron hydride at 1 bar of pressure, which also causes the proposed title to be preclude such iron hydride. Plasmic Physics (talk) 20:04, 5 December 2014 (UTC)

Does it relate to hydrogen dissolved in iron, or to hydrogen dissolved in iron hydride? Biscuittin (talk) 00:16, 6 December 2014 (UTC)

Are you referring to the statement: "The hydrogen in typical iron hydride may contribute up to 0.001% of its weight". How do we know this is at 1 bar pressure? The statement does not say so. Biscuittin (talk) 00:20, 6 December 2014 (UTC)

There is no distinction, we've settled that. It is a given that it is at 1 bar, since the high pressure forms at delt with in a dedicated section later in the article. Plasmic Physics (talk) 00:37, 6 December 2014 (UTC)

Biscuittin, you need to give up on this one. Clearly User:Plasmic Physics is incapable of making the article more clear, explaining himself in non-combative plain language, or of thoroughly citing his sources. Until another domain specialist comes along to clean the article up, there's no harm in leaving it as is, unless you want to become that domain specialist. It would be appropriate to tag it with Template:Refimprove or a cleanup template directed at translating esoteric science into appropriate encyclopedic language. Tarnas (talk) 01:48, 6 December 2014 (UTC)

I don't understand what you mean - I provided two references for what I written. What more needs to be referenced? Plasmic Physics (talk) 03:04, 6 December 2014 (UTC)

It would take quite a while to go through what you write, check for references, and then, if you give a reference, to check that the reference is relevant. Here we have a case of you writing something that is unreferenced, which has persisted for more than a year without anyone finding a reference for it: [4]

Here we have a large block of text that you write, which you don't provide any citations: [5]

Several days later you provide two citations, which is a good development. [6] But both of those citations look to me like padding. It looks to me like you found a reference (Itakura) that tangentially touches on this subject matter, and slapped that on both paragraphs, then later found Sakaki for the first paragraph. Since neither study appears to be free to view on the internet, and the abstracts have almost nothing to do with the paragraphs you are using them as references for, it looks suspicious. As I said to User:Biscuittin above, this is okay with me, but some day a domain specialist who can write for lay readers will find this article and tear it apart.

You also added an image of a barretter without adequate explanation. The page for Iron-hydrogen_resistor does not refer at all to iron hydrides or iron-hydrogen alloys. It does say that as the iron filament gets hotter, hydrogen solubility in the iron changes. A knowledgeable reader might therefore assume that a reversible, temperature-dependent alloy of iron and hydrogen is being created. But none of this is made explicit, and perhaps you can appreciate that the average wikipedia reader, even those who took chemistry in college, would not normally think of hydrogen as an alloy in a metal. That fundamental incongruity needs a bit of clear explanation. This would be an opportunity for you to find a way of making this unusual physical behavior clear to non-professional readers.

Here's one more example of you creating a large paragraph without a citation, the one for "Molecular hydrides" that includes the term "autopolymerisation": [7]

Do you want me to continue to mine your contribution history to show that you are not so diligent with references? I think if you can't see the trend, then I'm not going to convince you. This is okay, because as I've mentioned elsewhere, it looks like you are doing good work, and now we just need someone with your level of technical knowledge to come in and make all this understandable to non-professional readers, and there's no urgency in that. Tarnas (talk) 04:23, 6 December 2014 (UTC)

I have tried to clarify some of the confusing parts of the article. Though we still need a bit about the baretter to be written. Also how does hydrogen affect the properties of iron when dissolved in it? We have a number of statements suggesting there are changes, but we don't know what they are (apart from weakening). Graeme Bartlett (talk) 05:32, 6 December 2014 (UTC)

I don't think your recent edit was very helpful. The large paragraph you removed was not wrong, it just lacked context and a citation. Hydrogen roasting of iron ore is real though probably very uncommon. Tarnas (talk) 06:00, 6 December 2014 (UTC)

Ditto; one process facilitating hydrogen roasting, is the direct reduction method, which accounts for approximately 5% of globally produced iron. This is only one hydrogen roasting method. Plasmic Physics (talk) 09:45, 6 December 2014 (UTC)

Our article was implying that this was THE way to do it. Any way if it has a context that is relevant, eg that the iron produced is contaminated by hydrogen, then that should get a mention. Otherwise it is irrelevant. Graeme Bartlett (talk) 11:29, 6 December 2014 (UTC)

Here is a link that describes the view that hydrogen can act as an alloying element: [8]. There are many, many more, but this is just one that I plucked up from Google. I would like to think that clarifying the chemical-physics of iron-hydrogen resistors should be done on that article, not this article? 'Autopolymerisation', in its rawest sense, refers to polymerisation requiring negligible or no activation energy to proceed. Plasmic Physics (talk) 10:02, 6 December 2014 (UTC)

On the topic of iron-hydrogen resistors, it should get at least one sentence here about the topic, after all it is an application. The picture is as mentioned about without context of why it applies. The physics of this can also be included in this article if there is more known about it. Graeme Bartlett (talk) 11:29, 6 December 2014 (UTC)

The picture is simply meant to be an in situ illustration of iron hydride. Plasmic Physics (talk) 12:25, 6 December 2014 (UTC)

So that is why it is there. Does anyone call the filiament iron-hydride? Or just iron? Thanks for referencing the titanium statement though. Graeme Bartlett (talk) 13:08, 6 December 2014 (UTC)

It is also the only picture I could find. The filament is not 'just iron' though. As Tarnas correctly pointed out, its proper operation depends on the temperature-dependent dissolution of hydrogen into the iron matrix to form iron hydride. Ergo, it depends on the context of the description, whether 'iron' or 'iron hydride' is more apt a term to use. Since we know that it is iron hydride, and we want to reflect that aspect, why deviated from this article's established term? Plasmic Physics (talk) 22:28, 6 December 2014 (UTC)

Perhaps a reference to alloys and solid solutions would help. An alloy of two metals or a metal and psuedo-metal contribute to metallic orbitals. A solid solution would be H2 molecules floating and not reacting with Iron matrix. Third would be a compound Fe+2 and H- ions. Fact that filament conducts electricity would be the first two. TaylorLeem (talk) 20:23, 31 August 2020 (UTC)

Mentioning Raney Nickle and Raney Cobalt. Iron is a group 8 metal like the other two, however Hydrogen Nickle and Hydrogen Cobalt have much more documentation. My father was involved with plated wire memory (1960s) and yes you can plate Iron from aqueous solution. This led to Iron-Hydrogen problems published. TaylorLeem (talk) 20:35, 31 August 2020 (UTC)

Solid hydrogen

The phase diagram of hydrogen shows it can solidify when the pressure is high enough. I suspect better references are around though. The source for the article came from the listed reference. Graeme Bartlett (talk) 16:18, 7 December 2014 (UTC)

Other phase diagrams published: http://inspirehep.net/record/814075/plots http://www.pnas.org/content/110/20/8040/F1.expansion.html . Graeme Bartlett (talk) 16:28, 7 December 2014 (UTC)

This image seems to show that solid hydrogen occurs in the range of 5+ GPa and 1-5 Kelvin -- very cold, not room temperature (near 300K). It appears that other phase diagrams suggest solid or metallic hydrogen at temperatures well above 500K and at extreme pressures (100GPa+) that I'm not sure are possible to reproduce in a lab, but which apparently exist in planetary cores. Anyway, not 5GPa at room temperature. The listed reference (Shibazaki 2012) is not free to read. I don't know how to read log P or T units properly. Tarnas (talk) 16:52, 7 December 2014 (UTC)

Here is the original article, written by Mao, which the above cites: [9]. Plasmic Physics (talk) 22:09, 7 December 2014 (UTC)

I'm not sure if you're at university and can read all these articles you cite, but they are all behind paywalls for me and have extremely inadequate abstracts. For something as fundamental as the phase diagram for hydrogen, it's not going to cut it to support an non-intuitive claim with a paywalled article. Parameters of the solid phase of hydrogen would be "high priority" wikipedia content. I'm inclined to believe that hydrogen could indeed be solid at 300K and 5GPa, but that fact is not in hydrogen, solid hydrogen, or metallic hydrogen, and I have yet to find a freely readable document that described this phenomenon. Tarnas (talk) 22:52, 7 December 2014 (UTC)

Here's a phase diagram showing the melting curve intersecting room temperature at what could very well be 5GPa: Jephcoat 2011. It would be best if this phenomenon could be made explicit rather than hinted at obliquely. Tarnas (talk) 23:11, 7 December 2014 (UTC)

An even better graph: [10]. Another: [11]. A decent explanation of the research on p2/11 ¶2: [12]. Close enough for me to remove the dubious tag. Tarnas (talk) 23:33, 7 December 2014 (UTC)

Thanks for that. The pdfyou link gives 5.2 GPa. To assist with units, 5 Gpa is 50 kilobars, or 49,000 atmospheres pressure. This is found in the lower crust or mantle of the earth. Another thesis that is open to read is at http://www.diva-portal.org/smash/get/diva2:212813/FULLTEXT09.pdf with a diagram on page 42. Graeme Bartlett (talk) 01:36, 8 December 2014 (UTC)

Why the N-dash in the title?

In English, compound words are joined by a plain hyphen. The N-dash is an optional typographical markup used in fancy printed styles, when one of the terms being joined is itself a comppound or a multi-word name. That is not the case here. And, anyway, Wikipedia should prioritize contents and ease of editing by ordinary people -- not fancy typography.

Stable Iron Hydrogen alloys

Old Aldrichemica Acta, published by Sigma nee Aldrich Chemicals, Had an article about Raney hydrogenation catalyst alloys primarily Nickel with trace Al, Ca, La, etc. However also listed was FeTiH2. Note that Iron is catalyst for Hydrogenation of Nitrogen in the Haber process; important in that 5% of World's energy is used. Industrial issue, Electroplating also also introduces Hydrogen in the Iron/steel lattice. Interstitial protons (Hydrogen interaction with metallic orbitals) have high mobility. This from older CRC Handbook, table of mobilities in different metals. Electroless Nickel and Electroless Copper plating also introduce Hydrogen into Iron/steel plated metal. Electroless Copper plated on Copper does introduce Hydrogen into the plated metal. Hypophosphite and Formaldehyde provide Hydride for the electroless pocesses. TaylorLeem (talk) 19:15, 31 August 2020 (UTC)

Raney alloys

An older "Aldrichamica Acta" article noted Raney type alloys with other than Nickel. Raney Iron Titanium alloy could reversibly store Hydrogen, and showed catalytic activity. TaylorLeem (talk) 04:54, 21 November 2021 (UTC)