Preresonance Raman spectroscopy of the rhodium hexabromide anion

Raman spectroscopy was used in structural studies of solution‐phase RhBr 6 3− anions. The observed spectra are consistent with an octahedral ground‐state structure. Polarization measurements of the ν 1 (A 1g ) and ν 2 ( E g ) vibrational modes support the contention of cubic symmetry. The degree of polarization of these lines is independent of laser wavelength, not unlike observations of other d 6 hexahalide complexes. No resonance enhancement is observed with either T 1g or T 2g electronic transitions in the visible spectral region. Rather it is believed that the Raman transitions obtain intensity by way of virtual excitation of the allowed T 1u electronic transition in the near‐ultraviolet portion of the spectrum.