Cupric nitrite

The nitrite is only known in solution, prepared by addition of lead nitrite to cupric-sulphate solution. Exposure of its dilute solution to air causes slow formation of nitrate. On evaporation of a concentrated solution over sulphuric acid, there is partial decomposition in accordance with the equation

3Cu(NO₂)₂ = Cu(NO₃)₂ + 2CuO + 4NO.

It forms a number of complex nitrites with other metals.