Magnetic circular dichroism and absorption spectra of d° tetrahedral oxyanions and thioanions: MoS₄²⁻, MoO₄²⁻, WS₄²⁻, ReS₄⁻, VS₄³⁻, VO₄³⁻and OsO₄

Absorption and magnetic circular dichroism spectra have been measured for the tetrahedral d° ions MoS4 2-, MoO4 2-, WS4 2-, ReS4 -, VS4 3-, VO4 3- and OsO4 in the visible and ultra-violet spectral range. Comparison of the experimentally obtained MCD parameters with regard to their relative signs leads to the conclusion that probably the first two allowed longest wavelength electronic transitions of all these species have the same assignment (i.e., t 1 →2e and 3t 2 →2e, which seems likely on energetic grounds). An estimation of the MCD parameters by using eigenvectors from recently published molecular orbital treatments gave contradictory results.