M÷ssbauer studies in transition metal chemistry. I. Compounds of iron with Dithioacetylacetone (Pentane-2,4-dithione)

The temperature dependence of the Mossbauer spectra of some iron- containing compounds of dithioacetylacetone are reported between 4 and 293 K. ��� The quadrupole splitting ΔEq of [Fe(SacSac)3] is larger than usually observed for low-spin six-coordinated iron(III) and is ascribed to the lifting of orbital degeneracy of the 2T2 ground state by small axial and rhombic distortions. ��� The unsubstituted and phenyl-substituted dithiolium salts of [FeCl4]2- exhibit strongly temperature-dependent quadrupole splittings, which arise directly from the lifting of the orbital degeneracy of the 5E ground state due to distortion of the [FeCl4]2- tetrahedron.