Gas chromatog. and IR and Moessbauer spectroscopies were used to study the solid-state reactions between sodium nitroprusside (SNP) and Mn(II), Co(II), Ni(II), and Cu(II) chlorides under hydrogen atomsphere The presence of these metal salts influenced the thermal decomposition of SNP. CuCl2.6H2O reacted with SNP at room temperature to give Cu[Fe(CN)5NO].xH2O. At higher temperature, CoCl2.6H2O and NiCl2.6H2O reacted with SNP, and catalyzed the decomposition Only the reaction of MnCl2.4H2O and SNP was similar to that of the pure complex. A possible mechanism is discussed and kinetic parameters are reported.

Key words: REACTION MECHANISM, HYDROGEN, COPPER CHLORIDE, SOLID PHASE REACTION, MANGANESE CHLORIDE, COBALT CHLORIDE, NICKEL CHLORIDE, COORDINATE CHEMISTRY, SODIUM NITROPRUSSIDE