Crystal and molecular structure of tetraphosphorus pentaselenide

Abstract

P₄Se₅ has been isolated from the reaction of bromine with P₄Se₃ in carbon disulphide, and identified by crystal structure determination; the analogous reaction of bromine with P₄S₃ yields P₄S₅. The crystals of P₄Se₅ are orthorhombic, space group Pn2₁a, a= 12·79(2), b= 11·19(2), c= 6·66(2)Å, Z= 4. The refinement of site occupation factors for trial atoms facilitated the structure determination. The molecule has the same unusual cage structure as P₄S₅, but the crystals are not isostructural.