Electronic Energy Levels in Hexahalotellurate(IV) Complexes

D.A. Couch, C.J. Wilkins
Department of Chemistry
University of Canterbury
Christchurch, New Zealand

George R. Rossman, Harry B. Gray

  Arthur Amos Noyes Laboratory of Chemical Physics
California Institute of Technology
Pasadena, CA  91125


The electronic spectra of the octahedral TeCl62- and TeBr62- complexes are reported and assigned. The s → p transition a1gσ* → T1uσ* gives rise to three spin-allowed bands in TeCl62- (32,880; 34,480; 35,680 cm-1) and TeBr62- (28,470; 29,730; 30,850 cm-1). These data are taken as evidence that the excited singlet states are distorted to lower symmetry, probably C2v. The lowest allowed halide → Te(IV) charge transfer transitions are at 44,170 cm-1 and somewhat higher than 52,000 cm-1 in TeCl62- ; analogous transitions appear at 37,000 and 42,600 cm-1 in TeBr62-. The observed spectral data indicate that the “inert” 5s2 Te(IV) electrons, which reside in the a1gσ* level, are partially delocalized to the halide ligands.

Spectra at Temp

Electronic absorption spectra of a thin film of (n-Bu4N)2(TeCl6) th 300 and 18 K.

last updated: 25-Jul-2023