Optical spectra of the tetrahedral tetrabromocobalt(II) complex ion in molten tetrabutylphosphonium bromide

Abstract

Optical spectra of CoBr₄^2- in molten tetrabutylphosphonium bromide are recorded and the bands interpreted as due to charge-transfer and ligand-field transitions. The resolved spin-allowed bands are similar to those reported earlier in organic solvents. Cobalt(II)-bromide-rich mixtures with tetrabutylphosphonium bromide are found to supercool to a glassy material. The effect of temperature on these bands has also been studied.