Editing Copper(II) nitrate (section)

===Anhydrous copper(II) nitrate===
[[File:Copper(II)-nitrate-monomer-2D-dimensions.png|thumb|left|Structure of anhydrous copper(II) nitrate in the gas phase.<ref name="G&E" />]]

Two [[polymorphism (materials science)|polymorph]]s of anhydrous copper(II) nitrate, α and β, are known.<ref name="G&E" /> Both polymorphs are three-dimensional [[coordination polymer]] networks with infinite chains of copper(II) centers and nitrate groups. The α form has only one Cu environment, with [4+1] coordination,<ref name="Wallwork&Addison">{{cite journal |last1=Wallwork |first1=S. C. |last2=Addison |first2=W. E. |year=1965 |title=526. The crystal structures of anhydrous nitrates and their complexes. Part I. The α form of copper(II) nitrate |journal=J. Chem. Soc. |volume=1965 |pages=2925–2933 |doi=10.1039/JR9650002925}}</ref> but the β form has two different copper centers, one with [4+1] and one that is square planar.<ref name=Troyanov>{{cite journal |last1=Troyanov |first1=S. I. |last2=Morozov |first2=I. V. |last3=Znamenkov |first3=K. O. |last4=Yu |last5=Korenev |first5=M. |year=1995 |title=Synthesis and X-Ray Structure of New Copper(II) Nitrates: Cu(NO<sub>3</sub>)<sub>2</sub>·H<sub>2</sub>O and β-modification of Cu(NO<sub>3</sub>)<sub>2</sub> |journal=Z. Anorg. Allg. Chem. |volume=621 |issue=7 |pages=1261–1265 |doi=10.1002/zaac.19956210727}}</ref>

The nitromethane solvate also features "[4+1] coordination", with four short Cu-O bonds of approximately 200 pm and one longer bond at 240 pm.<ref>{{cite journal |last1=Duffin |first1=B. |last2=Wallwork |first2=S. C. |year=1966 |title=The crystal structure of anhydrous nitrates and their complexes. II. The 1:1 copper(II) nitrate-nitromethane complex |journal=[[Acta Crystallographica]] |volume=20 |issue=2 |pages=210–213 |doi=10.1107/S0365110X66000434 |doi-access=}}</ref>

Heating solid anhydrous copper(II) nitrate under a vacuum to 150-200 °C leads to sublimation and "[[Cracking (chemistry)|cracking]]" to give a vapour of monomeric copper(II) nitrate molecules.<ref name="G&E" /><ref>{{ cite journal | title = 628. The vapour pressure of anhydrous copper nitrate, and its molecular weight in the vapour state | first1 = C. C. | last1 = Addison | first2 = B. J. | last2 = Hathaway | journal = [[Journal of the Chemical Society|J. Chem. Soc.]] | year = 1958 | pages = 3099-3106  | doi = 10.1039/JR9580003099 }}</ref> In the vapour phase, the molecule features two bidentate nitrate ligands.<ref>{{cite journal |last1=LaVilla |first1=R. E. |last2=Bauer |first2=S. H. |year=1963 |title=The Structure of Gaseous Copper(II) Nitrate as Determined by Electron Diffraction |journal=J. Am. Chem. Soc. |volume=85 |issue=22 |pages=3597–3600 |doi=10.1021/ja00905a015}}</ref>