Talk:Copper(II) hydroxide

removed all the scrolling stuff! --негіднийлють ^{(Reply|Spam Me!*)} 06:40, 29 November 2005 (UTC)

Why is there such a detailed description of the home preparation of this compound? This isn't something that is synthesized on a laboratory scale anyways. Seems like something it's more suited for a Wikibook recipe. Chris Barile 05:50, 13 April 2007 (UTC)

Could anybody add an information about toxicity of this compound? It's created massively upon electrolysis, so it would be good to know how dangerous it is. User:Jakub Mareda today? (UTC) — Preceding unsigned comment added by Darker-jmareda (talk • contribs)

New Organization Proposal

I think that this article should be organized in a different way. Anything regarding the making of copper hydroxide should be under a new section called "manufacture", and anything regarding its uses should be under "uses". It should be added that it's also a pesticide (more general term than fungicide). And a more adequate table like the one on the copper sulfate article should be used rather than the one used right now in this article. Slartibartfast1992 22:19, 21 April 2007 (UTC)

Melting Point

I had put "decomposes to CuO" as the melting point because copper (II) hydroxide decomposes before it melts. For example, in boiling water the precipitate will rapidly turn to the black oxide. If you don't want to put this information under the melting point, it should at least be in the article somewhere as it is important. Chris Barile 05:07, 7 June 2007 (UTC)

Ah. Is there any exception, under special conditions maybe, where it ments at a certain point? If not, sorry to have intefered, feel free to add it in there. I suggest placing a dash first, then placing "decomposes into CuO" between parentheses. Slartibartfast1992 01:10, 8 June 2007 (UTC)

Never mind, you seem to have done that already. Also see you placed the standard table there. Looks good. Slartibartfast1992 01:12, 8 June 2007 (UTC)

No, I highly doubt that it ever melts under standard conditions because CuO is much more thermodynamically stable. Also, no literature mentions a melting point. I found a decompostion point of 185°C, which corresponds nicely with a book I have that states that the dry product is stable at 100°C. Lastly, should this article still be considered a stub? I've looked hard and can't find too much more noteworthy information. Chris Barile 01:31, 8 June 2007 (UTC)

Hmmm... I'll start a discussion called "stub?" so we can discuss the criterion for stubs and see how it applies to this article. I won't be available to discuss now, though. Maybe later on or tomorrow. Slartibartfast1992 02:15, 8 June 2007 (UTC)

The article is confusing. For melting point it decomposes at 80C but in the reactions section it decomposes at 180C. Should these not be consistant? —Preceding unsigned comment added by 136.206.1.49 (talk) 15:06, 3 July 2009 (UTC)

Stub?

I have the opinion that this article should remain a stub until we find some historical data on Copper Hydroxide. However, the article has advanced a lot, and once this information (maybe some more too) is obtained, we can remove the stub template. Any other opinions? Slartibartfast1992 02:16, 8 June 2007 (UTC)

I agree that a bit of history on chemical compounds is nice, but I can't find much information about Cu(OH)₂. I don't think copper hydroxide has an discoverer per se but it most probably was used by the alchemists (easily made with lye and blue vitriol). I did find this information in Watts (1872):

"Much of the blue verditer or Bremen green which occurs in commerce, consists of hydrated cupric oxide, prepared by precipitating a solution of sulphate of copper with caustic potash, washing the precipitate, again taking it with caustic potash, and lastly washing it thoroughly."

(Back then, it was mistakingly labeled it as hydrated cupric oxide written as CuO-H₂O.) It seems that blue verditer was historically an important pigment (http://www.naturalpigments.com/detail.asp?PRODUCT_ID=417-11B) so copper hydroxide was produced on an industrial scale.

I also think it may be good to add that several? minerals are comprised at least partially of copper hydroxide (ie azurite).

I can put together some sentences with this information if you think it should be included in the article. Chris Barile 05:32, 8 June 2007 (UTC)

That is plenty of information. We should include all uses in history under a section called "History", which, in my opinion, should be positioned first. Then I think that the sections "Synthesis" and "Reactions" should be merged under one section called "Chemical Properties" or something of the sort (personally, I think "Chemical Properties" is not that good, so I'll try to come up with something else). Uses nowadays should be put after that section. Finally, the last section (except for "See Also" and "References") should be "Copper Hydroxide in nature. I might be able to get a good picture of azurite for ths section.Slartibartfast1992 14:39, 9 June 2007 (UTC)

Wait, I read that link of yours, it said that that product was made of "the same Copper Carbonate that makes up azurite. That rules out two things: the placing of azurite as a mineral sample of Copper Hydroxide, and the using of your link as a reference. Slartibartfast1992 14:45, 9 June 2007 (UTC)

Azurite is chemically 2CuCO3 • Cu(OH)2, so it's part hydroxide and part carbonate. There are other minerals such as malachite with different ratios. In my opinion, I think it would still be considered useful to mention that copper hydroxide makes up part of these minerals. I think I read somewhere (will try to find where) that pure copper hydroxide does exist as a mineral, but this is very uncommon because carbon dioxide from the atmosphere converts the hydroxide to the carbonate. Chris Barile 21:10, 9 June 2007 (UTC)

That fact about carbon dioxide turning copper hydroxide into carbonate should definitely be included in the section "Copper Hydroxide in Nature". About the ratios in minerals, that should be the main point in that section. Examples such as Azurite and malachite should also be listed. Slartibartfast1992 04:18, 10 June 2007 (UTC)

I made the changes we discussed and went ahead and removed the stub since now there is a good amount of information. Chris Barile 20:54, 10 June 2007 (UTC)

Wow, you definitely took this article out of stubhood, if that's a word. Congratulations on a job well done. Slartibartfast1992 01:18, 11 June 2007 (UTC)

Finishing Touches

What more can be done to make this an 'A' article? I agree with the decision to remove the 'how to' section. I initially proposed this quite a long time ago. I've fixed the structure error in the hydrazide reaction (at least I think I did so correctly...it's really late right now!). I might be able to take some pictures of some nice copper hydroxide crystals. Chris Barile 11:19, 1 November 2007 (UTC)

Oh and the source for the organic reagent section is Paquette, Leo A. (1995). Encyclopedia of Reagents for Organic Synthesis, 8 Volume Set. Wiley. ISBN 0-4719-3623-5. I'm not sure why the last two references there are labeled 1 and 2, maybe somebody can fix this for me? Chris Barile 11:23, 1 November 2007 (UTC)

The ones previously in the references section are actually footnotes, since they adhere to only one sentence (the numbers as superscript beside a sentence). The latter two are references, so they don't go with only one particular sentence. I'll fix this. --Slartibartfast1992 22:12, 1 November 2007 (UTC)

What is shown in the picture? A chlorate cell?  Dan Smith70.171.235.149 (talk) 15:34, 20 November 2007 (UTC)

It is a picture of the electrolysis of a solution of a soluble copper salt to form copper hydroxide. This procedure was previously described in older versions of this article, but it has since been deleted (not entirely sure if this was 100% justified). Chris Barile (talk) 09:43, 6 December 2007 (UTC)

Copper II hydroxide - copper II oxide equilibrium

I have a question about the equilibrium condition that exists between copper II hydroxide and copper II oxide. Here is the reaction: Cu(OH)₂ heat ←→ CuO H₂O When heat is added, it drives the equilibrium to the right, forming more copper II oxide. When it is exposed to excessive moisture, it absorbs water to form copper II hydroxide again. But why does copper II hydroxide turn into copper II oxide when it is moist? I think that that would contradict Le Chatalier's principle. Just a question. --Cheminterest (talk) 20:25, 16 March 2010 (UTC)

Addition on crystal structure

There are several reported crystal structures of copper(II) hydroxide. I do not agree that it is impossible to prepare it pure. I will soon add figures from these structures. As copper(II) hydroxide forms 1-dimensional chains, it clearly provides a reason for its low solubility in aqueous media. Dr InorgChem (talk) 11:38, 25 March 2017 (UTC)

Because I am still new here, I can not upload a figure on the crystal structure. If anyone else is interested can do it for me. Otherwise it will come after several days.

Ball and stick representation of a fragment of the crystal structure of copper(II) hydroxide. The structure depicts linear chains of copper(II) hydroxide exhibiting hydrogen bonding. Color code: Cu = orange, O = red and H = white spheres.

I also think that the figure on azurite in this article is misleading. Sure it is a related structure, but if we do not show the structure of copper hydroxide, what is the point to bring it here, unless there is some other interest.

At the introduction there are two figures of copper(II) hydroxide, I do not see how the second one adds to the quality of the article. It just simply shows the coloro, nothing much. Dr InorgChem (talk) 13:27, 25 March 2017 (UTC)

Agreed that the additional picture is redundant, perhaps the electrolysis jar could be moved. I added the azurite as an example of one of the common cupric hydroxides. There are many but azurite is famous because the mineral is so common. About the structure of real Cu(OH)2, the main need is to add for a reference. We usually rely on reviews for references, but for crystal structures it is probably a good idea to add the actual Xray paper. Add the doi. Be careful this time around. --Smokefoot (talk) 14:37, 25 March 2017 (UTC)

Dear Smokefoot, Thank you for your valuable input. It is common sense that encyclopedia articles rely mostly on reviews. Here I would add that concept and perspective articles should be considered in future without much problem. That is why on 21.03.2017 a concept citation and a short paragraph was inserted to this article. I agree with you that review articles do not publish CIFs, so original paper have to be used and cited. I am not sure how to interpret your comment "be careful" found both in your message and in the changes caption, however I am very grateful to you for giving me hard time with this articles. It has helpful to me to understand what is wrong with wikipedia lately and how it can be improved. For my current personal views, you can get more information here: http://www.kondinski.com/2017/03/27/how-can-we-develop-wikipedia-articles-that-we-can-trust/ . Thanks and all the best! Dr InorgChem (talk) 08:00, 27 March 2017 (UTC)

I'll take a look later at your essage, but I did see that you seem to praise ResearchGate. which seems to be a predatory money-making site that preys on ego's of scientists. I avoid it.

If you see something that is incorrect in Wikipedia Chemistry, leave a message at the project page. Wikipedia talk:WikiProject Chemistry. The problem will be repaired quickly. I and others would be interested in specific areas where you think that problems exist.

A great threat to Wikipedia is the continuing battle with scientist's egos and their wish to cite themselves. They all want to promote their own papers. Period. New editors appear regularly who think that they can "help", but what they always do is discuss papers that cite themselves or their friends. I have been at this business for 10 years and the pattern is consistent. Famous people, normal young chemists, everyone - they all want to "help" by citing their latest report in the Journal of Narrow Results. Chemists do not realize the scale of the publication business. Look at the edit history of quantum dot or molybdenum disulfide. Several papers published per day on these topics. Good luck with your editing.

And dont forget to add the ref to Cu(OH)₂ Xray. I have been looking for this paper. --Smokefoot (talk) 13:27, 27 March 2017 (UTC)

This is the doi: https://doi.org/10.1107/S0108270195006230 . I will have to re-upload the image, otherwise I am not sure how to edit it directly. Dr InorgChem (talk) 13:44, 27 March 2017 (UTC)

For what its worth there's a preexisting image on commons (shown right). --Project Osprey (talk) 14:50, 27 March 2017 (UTC)

I was not aware. It looks better than that I have made so I changed in the new version. Dr InorgChem (talk) 14:56, 27 March 2017 (UTC)

OK, now we are in business for Cu(OH)₂. I thought maybe brucite structure.

Once again, I hear many people say that Wiki-chem is not reliable. Translation: (1) Wikipedia does not cite me or my friends or (ii) arrogance. I am not aware of any mistakes on the chemicals pages. Surely they exist, but we address problems quickly. There are indeed many gaps. Most articles are short, but brevity is a strength of Wikipedia. We are WP:NOTTEXTBOOK, WP:NOTJOURNAL, WP:NOTMANUAL, and WP:NOTNEWS. --Smokefoot (talk) 15:17, 27 March 2017 (UTC)

One other tip: do not add your personal observations. We call that OR (=original research). It is forbidden. I am sure your observations are valid, but dont include them in this encyclopedia (otherwise my mother would have added notes about her secret formula to kill ants, and my uncle would add recipes for curing headaches, etc). --Smokefoot (talk) 20:13, 27 March 2017 (UTC)

Illustration

Check out today's new editor's work here. Is that user editing Wikipedia to help readers? Or help themselves?--Smokefoot (talk) 13:57, 30 March 2017 (UTC)

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Amphoteric or Strong Base?

The introduction states that cupric hydroxide is a strong base but the Reactions section says it is amphoteric. However, as far as I know amphoteric substances have a pH value close to that of neutral substances and hence couldn't be a strong base. So this should probably be reviewed. Susmitauri (talk) — Preceding undated comment added 06:22, 19 November 2021 (UTC)

Melting point/decomposition point unclear.

The datasheet says 80°C, the english ttext at reactuons says 100°C, the hungarian page says 185°C. What's going on? Frigyes06 (talk) 05:57, 22 April 2022 (UTC)

unlike melting, decomposition is not a well-defined phase transition. Consequently, no particular temperature can be assigned. Sort of dissatisfying, but that's the way it is. --Smokefoot (talk) 12:45, 22 April 2022 (UTC)