The thermal decomposition of Ni(NO3)(2).6H(2)O (1), Ca(NO3)(2).4H(2)O (2) and nitryl/nitrosyl nitrato nickelate(II), NO2/NO[Ni(NO3)(3)] (3), was investigated by thermogravimetric measurements with quasi-isothermal conditions and compared to Co(NO3)(2).6H(2)O. Therespective decomposition processes of 1 and 2 differ from each other showing that at one hand anhydrous Ca(NO3)(2) was obtained whereas anhydrous nickel dinitrate has not be formed due to redox and condensation reactions. Instead basic nickel compounds have been formed. In reducing atmosphere nickel metal can be obtained. Anhydrous Ni(NO3)(2) results by the thermal degradation of nitryl/nitrosyl nitrato nickelate. FF-Raman spectra have been of help in the judgement of the decomposition processes. (c) 2007 Elsevier B.V. All rights reserved.