The title compound [Ni(MCZ)3J (NG^^" H2O was prepared by reaction of the aqueous solutions of nickel nitrate and methylcaxbazate (MCZ) . The crystal structure of [NKMCZ^KNO.^'EkO was determined by using single crystal diffraction techniques and crystalline was in monoclinic system with space group P2\/n. The unit cell parameters are as follows: o = 1.3681(2) nm, 6=0.8188(1) nm, c = 1.6029(4) nm, β= 92. 16(2)°, V= 1.7943(6) nm~3, Z = 4, F(000) =976, D_c= 1.744 g·cm~(-3), μ(Mo Kα) = 1.166 mm"1. Positional and thermal parameters were refined by the full-matrix least-squares method. All the non-hydrogen atoms were refined anisotropically but the hydrogen atoms were refined isotropically with the final factor values of R_1 = 0.0337 and wR_2 = 0.0857. In the title compound, methylcaxbazate serves as a bidentate ligand coordinating to the nickel cation with oxygen atom from carbonyl and the nitrogen atom from hydrazine group so that a five- membered chelating ring is formed. There are three rings in the molecular structure. The coordination number is six and the configuration is octahedral. In the environment of the molecule there are two NO_3~- and one crystal water molecule, which are linked with the inside by electrostatic force and hydrogen bonds. TheiTnal decomposition mechanisms of the compound were characterized by using TG-DTG, DSC and IR techniques. It was confirmed that decomposing processes of the compound include one endothermal and three continuous exothermic stages, residue is NiO at 325 ℃ , finally.

Key words: HYDRAZINE, FORMIC ESTER, NICKEL NITRATE, CRYSTAL STRUCTURE, THERMOLYSIS, DSC, IR