Cr(OAc)2 replaces the Fe(III) of [Fe2MO(OAc)6(H2O)3].nH2O. Their crystals are isomorphous according to the obtained cell parameters. The crystal structure of [FeCrCoO(OAc)6py3].py was determine trigonal, space group R32, a 1.7516, c 1.1027 nm, Z = 3, R = 0.040, Rw = 0.053. The electronic spectra [CrFeMO(OAc)6py3] in pyridine solvate were investigated. The d-d transition bands of the corresponding metal ions were assigned, and their ligand field parameters were calculated with ligand field theory.

Key words: CRYSTAL STRUCTURE DETERMINATION, PYRIDINE P, IRON COMPLEX, COBALT COMPLEX, NICKEL COMPLEX, POLYNUCLEAR COMPLEX, MANGANESE COMPLEX, LIGAND FIELD THEORY, CHROMIUM COMPLEX, ACETATE