Mechanism of thermal decomposition of hydrated copper nitrate in vacuo

The general scheme of three-stage thermal decomposition of Cu(NO3)2·3H2O to CuO has been refined based on evolved-gas-analysis data with a quadrupole mass analyzer (Jackson et al., Spectrochim. Acta Part B, 50 (1995) 1423). Quantitative evaluation of the composition of the gaseous products shows that the first stage involves primarily deaquation, and the second stage, primarily denitration of the original hydrated nitrate. The basic nitrate formed in the second stage most probably has the formula Cu(NO3)2·3Cu(OH)2. It has been established that the molecular oxygen observed in the third stage of decomposition is produced by catalytic decomposition of NO2 on the surface of CuO. The presence of Cu-containing ions in all stages of the process is consistent with the gasification mechanism of thermal decomposition.