Crystal structure of rhenium oxide tetrachloride

Abstract

Crystals of rhenium oxide tetrachloride are monoclinic, Z= 8, space-group p2₁/c, a= 12·61 ± 0·02, b= 5·76 ± 0·01, c= 18·51 ± 0·02 Å, β= 115·5 ± 0·3°. The structure was refined by three-dimensional least-squares methods to 0·069 for 954 reflections. The two crystallographically different ReOCl₄ units in the crystal have a square-pyramidal arrangement, with dimensions the same, within experimental error. The mean Re–O distances are 1·63, and mean Re–Cl 2·26 Å. The molecular units are weakly associated into dimer and endless chain arrangements through long Re ⋯ Cl interactions (3·55 and 3·65 Å) which are trans to the Re–O bonds.