Two binuclear nickel(Ⅱ) complexes of formula {[(tacn)Ni(H~2O)]~2(μ- C~2O~4)}I~2·2H~2O(1) and {[(tacn)Ni(H~2O)]~2(μ-C~2O~4)}(ClO~4)~2· 2H~2O(2), where tacn=1,4,7-triazacyclononane, have been synthesized. The crystal structures show that nickel(Ⅱ) ions are bridged by oxalate and each nickel(Ⅱ) coordinates with three nitrogen atoms of tacn and one water molecule to form octahedron. the hydrogen bonds were observed between coordinated water and lattice water molecules. The solid reflection spectra and solution absorption spectra of 1 and 2 have been measured.

Key words: NICKEL COMPLEX, CRYSTAL STRUCTURE, DINUCLEAR COMPLEX