Trinuclear complexes M[Co(en)2(SO3)2]2(H2O)2•4H2O (M=Mn, Fe, Co, Ni, Cu, Zn):: Their utilization for stoichiometric spinel oxides and the crystal structure of Ni[Co(en)2(SO3)2]2(H2O)2•4H2O

Trinuclear complexes of the general formula M[Co(en)(2)(SO3)(2)](2)(H2O)(2). 4H(2)O (M=Mn, Fe, Co, Ni, Cu, Zn) were synthesized. The crystal structure of one of the compounds in the series, Ni[Co(en)(2)(SO3)(2)](2)(H2O)(2). 4H(2)O were determined by single crystal X-ray diffraction studies. It crystallizes in a monoclinic unit cell (a=10.079(1), b=11.560(1), c=12.699(1) Angstrom, beta=101.8(1)degrees, V=1448.4(2) Angstrom(3)). In the structure, a nickel atoms is bonded to two [Co(en)(2)(SO3)(2)](-1) through the oxygen atoms of the sulfite ligands that have Co-S bonds. Thermolysis of the com plexes for M=Mn, Co, Cu, Zn in air at as low as 750 degrees C resulted in spinel oxides while the M=Ni compound resulted in a solid solution of rock salt type CoO and NiO. The Fe complex did not produce a single phase oxide but a mixture of M2O3 (M=Fe, Co) and spinel type compound.