About Defined Compounds in the Cu–In–Se System

Abstract

From the back reflexion X-rays diagrams, two defined compounds were evidenced in the copper deficient region in the Cu–In–Se system, (a) A cubic phase ( a =11.533(1)Å) belonging to the space group P 4̄3 m, in which the atomic positions were refined on the basis of the formula Cu 8 In 18 Se 32 . A possible electronic disorder of 1.75% cannot be ruled out leading to the formula Cu 8.5 In 18.5 Se 32 . (b) A quadratic phase corresponding to Cu 7 In 19 Se 32 , with a =11.511(1)Å and c =11.503(2)Å. A paracrystalline region was found between these two defined compounds.