Crystal structure of tetra-arsenic tetraselenide

Abstract

The title compound has been shown by X-ray single-crystal study to be isostructural with α-realgar, As₄S₄. Least-squares refinement of the structure gave R 0·11 for 1008 observed photographic reflections. The far-i.r. spectrum consists of As–Se stretching (205–253) and bending bands (93–135 cm^–1). Mean distances: As–As 2·56₅ and As–Se 2·39 Å. Crystals are monoclinic, space group P2₁/n, Z= 4, a= 9·63 ± 0·02, b= 13·80 ± 0·04, c= 6·73 ± 0·02 Å, β= 107·8 ± 0·5°.