Polarized absorption spectra and polarized Raman spectra of single crystals of trans(Cl2)-[CoCl2(NH3)n(H2O)4−n]Cl complexes (n = 2, 3, 4)

The title cobalt(III) complexes have been investigated by polarized absorption and Raman spectroscopies of the single crystals. The symmetry properties of the d-electron orbitals and of the vibrational modes attributable to the Raman bands of trans(Cl2)-[CoCl2(NH3)n(H2O)4−n]Cl complexes (n = 2, 3, or 4) were examined to elucidated the peculiar observation that ligand substitution causes no splitting of the 15 200-cm−1 absorption band and the 250-cm−1 Raman band. Effects of replacing the NH3 ligand with H2O on the electronic structure, atom–atom force constants and vibrational modes of these complex ions are briefly described.