The Structure and Physical Properties of μ-oxo-bis{oxotrichloro(O-perrhenylchloride)rhenium(VI)}, and the Non-existence of β-ReOCl3

Abstract

The compound previously reported as β-ReOCl3 has been shown by analysis and single crystal X-ray diffraction to be μ-oxo-bis{oxotrichloro(O-perrhenyl chloride)rhenium(VI)}, (Re2O3Cl6)(ReO3Cl)2. The crystals were triclinic, a = 6.112(5), b = 12.876(9), c = 6.020(5) Å, α = 88.30(5), β = 95.88(5), γ = 105.36(5)°, [Formula: see text]. Intensities were measured by a densitometer from photographs recorded on an integrating precession camera. The structure was refined by full matrix least squares to give a final R2 of 0.072. The molecule is composed of a dimeric Re2O3Cl6 unit with a bridging oxygen atom on the center of symmetry and an Re—O (bridge) distance of 1.847(1) Å. The remaining oxo-group on each rhenium is cis to the bridge and is strongly bonded (1.69(2) Å), and the position trans to the terminal oxo-group is filled by a weak bond to an oxygen atom of a perrhenyl chloride molecule. The infrared spectrum of the compound has been explained in terms of the structure.