Thermal decomposition of Cu(NO3)2•3H2O at reduced pressures

Thermolysis of Cu(NO3)(2).3H(2)O is studied by means of XRD analysis in situ and mass spectral analysis of the gas phase at P = 1/10 Pa at low heating rate. It is shown that stage I of the dehydration (40-80 degreesC) results in the consecutive appearance of crystalline Cu(NO3)(2).2.5H(2)O and Cu(NO3).H2O. Anhydrous Cu(NO3)(2) formed during further dehydration at 80-110 degreesC is moderately sublimed at 120-150 degreesC. Dehydration is accompanied by thermohydrolysis, leading to the appearance of Cu-2(OH)(3)NO3 and gaseous H2O, HNO3, NO2, and H2O. The higher pressure in the system, the larger amount of thermohydrolysis products is observed. The formation of the crystalline intermediate CuOx(NO3)(y) was observed by diffraction methods. Final product of thermolysis (CuO) is formed at 200-250 degreesC. (C) 2003 Elsevier Science B.V. All rights reserved.