Talk:Copper(II) nitrate

This page appears to have been moved from its correct place. Wikipedia encourages the use of correct Stock nomenclature in the title pages of articles on chemical compounds (see Wikipedia:Naming conventions (chemistry)): however, there is no space between the name of the element or ion and the parenthesis indicationg the oxidation number, as a quick look through Category:Chemical compounds and its subsections will confirm. See also Inorganic nomenclature, Wikipedia talk:WikiProject Chemicals and [1]. Physchim62 13:21, 24 May 2005 (UTC)

I've gone ahead and corrected this. - UtherSRG 13:40, May 246, 2005 (UTC)

It's not exactly encyclopedia-like. It does make it a little more entertaining, though, which isn't a bad thing. What joke!!!??? 71.168.108.66 18:24, 15 January 2007 (UTC)

In chem lab, I spilled a bit of 1M CuNO3 on my hand and the skin turned blue in the parts where it came into contact. I think I also got a few drops of 1M AgNO3 on my hand and the skin turned black in those parts. I didn't notice anything until the day after. Just want to point out that CuNO3 isn't that corrosive. I think that the nitrate reacts with my hand and leaves the copper behind making the skin kinda blue. 96.60.76.205 (talk) 05:47, 24 November 2008 (UTC)

Wrong MSDS is attached --REALLY WRONG!

The attached MSDS makes this stuff look like the ultimate oxidizer. Cu(I)NOx may be, but.....PLEASE check asap74.108.139.186 (talk) 21:07, 15 October 2009 (UTC)

Caption

The caption for the photo of the aqueous solution says "Aqueous solution of copper(II) nitrate, which contains [Cu(H2O)6]2+ ions." The solution looks green. Isn't [Cu(H2O)6]2+ blue? It is my understanding that concentrated solutions of copper nitrate look green because they still have ions with nitrate coordinated to the copper, while dilute solutions look blue because the nitrate is replaced by water. Now, I suppose it is true that even a concentrated solution contains some [Cu(H2O)6]2+, but the real question is what is useful to say in such a caption without misleading or confusing the reader. I'd just say "Aqueous solution of copper(II) nitrate", which is more or less what the caption used to say until recently. --Itub (talk) 03:52, 15 January 2012 (UTC)

I agree, its redundant and confusing to mention the metal ion. Why not throw in the nitrate ion as well. Doesn't make much sense. The only purpose it serves is to inform the reader that the metal ion forms an octahedral metal aquo complex, although this information would be better somewhere else, as it may lead some readers to believe that there is a distinction between a regular solution of Copper(II) nitrate and a solution containing [Cu(H2O)6]2+ ions. Which of course, there is no real difference, so it needs to be changed. Explodo-nerd (talk) 09:54, 15 January 2012 (UTC)

I was the one expanding the caption. Not sure what the sample really was made from, since the contributor didn't say. I suspect it is from dissolving copper metal in nitric acid, in which case it would contain some NO₂. --Smokefoot (talk) 13:41, 15 January 2012 (UTC)

I think I remember once dissolving copper nitrate in water, and was fascinated by how it's green when you add a little water but then it turns blue when you add more water. So I know the phenomenon firsthand. :) I say "I think", however, because now that I've been trying to look for a reference to back that up, I find plenty of sources describing that behavior for copper chloride (even the WP article shows it), but none for copper nitrate. So maybe I misremembered the anion! (It was maybe 20 years ago.) But if any of you have some copper nitrate close at hand, perhaps you can try it (yes, I know, no original research, but I just want to know.) --Itub (talk) 14:25, 15 January 2012 (UTC)

I'm starting to think that you are right that the photo may be of copper recently dissolved in nitric acid. --Itub (talk) 14:42, 15 January 2012 (UTC)

Crystal structures of anhydrous and hydrated copper(II) nitrates

I've seen a bit of activity on this article today. Based on some of the comments on talk pages, we need clarification of the crystal structures of anhydrous and hydrated copper(II) nitrates. I've looked up and found structures for the alpha and beta forms of anhydrous Cu(NO₃)₂ and for Cu(NO₃)₂·nH₂O, n = 1, 1.5, 2.5, 3, and 6. Who wants to know what? --Ben (talk) 15:25, 15 January 2012 (UTC)

Well, for me, the main message would be that nitrate is coordinated less as the degree of hydration increases. Although that trend might be obvious to an inorganic chemist, it would not be to a usual reader. We should mention the five hydrates and then describe the structure of the most common one, which is probably the trihydrate. I couldn't figure out how to search for the entire set - what did you do? (I was searching Acta Cryst). If you are feeling energetic, you could enter the individual members and the refs in water of hydration, which is kind of a nifty compilation. Maybe explodonerd would be interested in helping out, kind of a project...--Smokefoot (talk) 15:56, 15 January 2012 (UTC)

I searched a database. Yep, we can say something about the trend, good idea. The trihydrate is tricky because the structure determination looks half-baked. The journal it's published in is a warning sign.

Here are the references for now:

• α-Cu(NO₃)₂: S. C. Wallwork, W. E. Addison, J. Chem. Soc. (1965) 2925-2933, File:Copper(II)-nitrate-anhydrous-xtal-1965-Cu-coordination-CM-3D-balls.png
• β-Cu(NO₃)₂: S. I. Troyanov, I. V. Morozov, K. O. Znamenkov, Yu. M. Korenev, Z. Anorg. Allg. Chem. (1995) 621, 1261–1265
• Monohydrate, Cu(NO₃)₂·H₂O: S. I. Troyanov, I. V. Morozov, K. O. Znamenkov, Yu. M. Korenev, Z. Anorg. Allg. Chem. (1995) 621, 1261–1265
• Sesquihydrate, Cu(NO₃)₂·1.5H₂O: K. Dornberger-Schiff, J. Leciejewicz, Acta Cryst. (1958) 11, 825–826
• 2.5-hydrate, Cu(NO₃)₂·2.5H₂O: B. Morosin, Acta Cryst. (1970) B26, 1203–1208
• Trihydrate, Cu(NO₃)₂·3H₂O: J. Garaj, Sbornik Prac. Chem. -Technol. Fak. Svst, Cskosl. (1966) 35–39 — structure looks very questionable!
• Hexahydrate, i.e. [Cu(H₂O)₆](NO₃)₂: R. Zibaseresht, R. M. Hartshorn, Acta Cryst. (2006) E62, i19–i22

α- and β-Cu(NO₃)₂ are fully 3D coordination polymer networks. The alpha form has only one Cu environment, with [4+1] coordination, but the beta form has two, one with [4+1] and one just four-coordinate square planar.

Cu(NO₃)₂·H₂O forms 2D sheets with bridging nitrates and H-bonding between sheets. Each Cu is [4+1], with one coordinated water molecule and four coordinated nitrates. Two of the nitrates bridge to another Cu centre like this: Cu–O–N–O–Cu. The other two bridge using just one oxygen atom, i.e. Cu–O···Cu. The O···Cu is the longer bond, the +1 in [4+1], at 2.33 Å. The four shorter bonds are all 1.9–2.0 Å.

Cu(NO₃)₂·1.5H₂O has only the copper atoms located, so I can't say much about its structure.

Cu(NO₃)₂·2.5H₂O is really a linear coordination polymer of [Cu(NO₃)₂(H₂O)₂] with bridging nitrato groups and a free water molecule hydrogen-bonded to two nitrates and two coordinated waters. H-bonding between coordinated waters on one chain and nitrates on adjacent chains stabilises a 3D hydrogen-bonded network.

Cu(NO₃)₂·3H₂O has only the copper atoms and some oxygen atoms located. One of the Cu–O bonds is very short, at 1.25 Å. There's not much I can say reliably about this structure because it's incomplete.

Cu(NO₃)₂·6H₂O is [Cu(H₂O)₆](NO₃)₂, with the [Cu(H₂O)₆]²⁺ ions apparently not exhibiting Jahn-Teller distortion, or not observably so. Six coordinated water molecules all with Cu–O distances of 2.0–2.1 Å. The uncoordinated nitrate ions participate in hydrogen bonding with the coordinated waters, forming a 3D H-bonded network.

In summary:

Water molecules in total	Coordinated waters per Cu	Coordinated nitrates per Cu
0	0	4
1	1	3+1
2.5	2	2+1
6	6	0

Ben (talk) 16:03, 15 January 2012 (UTC)

Great stuff. I also noticed that hexaaquo paper described no Jahn-Teller attributed to the effects of hydrogen-bonding. If you don't get around to inserting this material, I or someone else will. The main thing is that there are many hydrates, and a similar situation probably applies to the nitrates of other aquated divalent metals - Ni, Co, Fe, Mn, but nitrate might not be compatible with the early reducing metals. I will look around because it would be helpful to have a similar blurb for several articles.--Smokefoot (talk) 16:50, 15 January 2012 (UTC)

OK, great. I'm currently a bit busy with some other work on Cu(II) that's more likely to get me a qualification, but we'll see how it goes. It'd be a good addition to Wikipedia to describe some general trends in these transition metal nitrates. In books like Greenwood & Earnshaw, they systematically cover the halides, oxides, and other binary compounds of each element, but nitrates, sulfates, and so on are usually only mentioned if they're important, interesting or unusual in some way. I thought getting the facts down on 'paper' quickly might avert any more speculation about coordination numbers. --Ben (talk) 17:23, 15 January 2012 (UTC)

Balanced Chemical Equation?

Sorry, I'm just preparing an exam and I noticed the equation Cu + 4 HNO3 → Cu(NO3)2 + 2 H2O + 2 NO2 is not balanced. Actually I tried to read what it's written above here, but to be honest i don't understand. Pleasemake some reference in order to let people (like me) know if the the equation is right for some reason. Thank you in advance, Marco79.1.219.82 (talk) 11:31, 22 February 2012 (UTC)

The equation is balanced. Explodo-nerd (talk) 01:10, 23 February 2012 (UTC)

The left hand side of the equation has one copper, four hydrogens, four nitrogens and twelve oxygens, i.e. CuH₄N₄O₁₂.
The right hand side of the equation has one copper, four hydrogens, four nitrogens and twelve oxygens, i.e. CuH₄N₄O₁₂.
It is therefore balanced. --Ben (talk) 01:46, 23 February 2012 (UTC)

Menke nitration requirement?

Does the Menke nitration require anhydrous copper nitrate or is the acetic anhydride used to remove the water?150.227.15.253 (talk) 17:33, 3 January 2022 (UTC)