Editing Copper(II) nitrate (section)

===Hydrated copper(II) nitrate ===
Hydrated copper nitrate is prepared by treating copper metal or its oxide with [[nitric acid]]:<ref name=Ullmann/>

:{{chem2|Cu + 4 HNO3 -> Cu(NO3)2 + 2 H2O + 2 NO2}}
The same salts can be prepared treating copper metal with an [[aqueous solution]] of [[silver nitrate]].  That reaction illustrates the ability of copper metal to reduce silver ions.

In aqueous solution, the hydrates exist as the [[aqua complex]] {{chem2|[Cu(H2O)6](2+)}}. Such complexes are highly labile and subject to rapid ligand exchange due to the d<sup>9</sup> electronic configuration of copper(II).

Attempted dehydration of any of the hydrated copper(II) nitrates by heating affords the oxides, not {{chem2|Cu(NO3)2}}.<ref name="G&E" /> At 80&nbsp;°C the hydrates convert to "basic copper nitrate", {{chem2|Cu2(NO3)(OH)3}}, which converts to {{chem2|CuO}} at 180 °C.<ref name=Ullmann/> Exploiting this reactivity, copper nitrate can be used to generate [[nitric acid]] by heating it until decomposition and passing the fumes directly into water. This method is similar to the last step in the [[Ostwald process]]. The equations are as follows:

:{{chem2|2 Cu(NO3)2 -> 2 CuO + 4 NO2 + O2}}
:{{chem2|3 NO2 + H2O -> 2 HNO3 + NO}}

Treatment of copper(II) nitrate solutions with [[triphenylphosphine]], [[triphenylarsine]], and [[triphenylstibine]] gives the corresponding copper(I) complexes {{chem2|[Cu(EPh3)3]NO3}} (E = P, As, Sb; Ph = {{chem2|C6H5}}).  The group V ligand is oxidized to the oxide.<ref>{{cite book |last1=Gysling |first1=Henry J. |title=Inorganic Syntheses |series=Inorganic Syntheses |year=1979 |volume=19 |pages=92–97 |chapter=Coordination Complexes of Copper(I) Nitrate |doi=10.1002/9780470132500.ch19 |isbn=9780470132500}}</ref>