In water, a calcium( II ) complex with 2-oxo-propionic acid salicyloyl hydrazon (C_(10)H_(10)N_2O_4) has been synthesized. The yellow wystals of the calcium ( H ) complex was obtained in a mixed solvent of DMF and DMSO. The formula of the complex is [Ca_2(C_(10) H_8N_2O_4)_2(DMSO)_2(H_2O)_4] ·2DMSO (C_(10)H_8N_2O_4~(2-) is the dinegative ion of 2-oxo-propionic acid salicyloyl hydrazone) . The crystal structure was determined by X-ray single crystal diffraction analysis. The results show that the complex is monoclinic of space group P2(1)/c, the cell parameters are as follows: a = 1.0634(3) nm, b = 1.7035(5) nm, c = 1.2183(3) nm, β = 106.180(5)°, V = 2.1192(10) nm~3, D_c= 1.412 Mg·m~(-3), Z = 2, F(000)=944, μ =0.534 mm~(-1), GOF = 0.861. The complex is a binuclear Ca complex, with one O atom of the carboxyl of 2-oxo-propionic acid salicyloyl hydrazone bridging two Ca. Each Ca atom is pentagonal bipyramid coordinated by two O atoms and one N atom of tridentates C_(10)H_8N_2O_4~(2-) ligand, one O atom of DMSO molecule and the O atoms of two H_2O. One H_2O and one DMSO locate at the apical position. In the crystal cell, there are free DMSO which are connected with H2O by hydrogen bonds. Because of the hydrogen bonds the complex formed a two-dimensional network structure in space. The thermal stability of the complex was studied by TG-DTG analysis.

Key words: CALCIUM COMPLEX, HYDRAZONE P, DIMETHYLFORMAMIDE, RETICULAR FORMATION, THERMAL DECOMPOSITION, CRYSTAL STRUCTURE, STABILITY