Crystal structures of two quenched CuInSe phases

The crystal structures of the δ‐phase with a composition of Cu 0.46 In 1.18 Se 2.00 and of a Cu‐poor β‐phase with a composition of Cu 0.39 In 1.20 Se 2.00 , both quenched from 750 °C, have been determined with single crystals. The δ‐phase crystallizes with a = 576.2(4) pm in the ZnS‐type structure (space group F 4 3m), the β‐phase with a = 575.5(3) pm, c = 1152.0(4) pm and Z = 4 in a new structure type for tetrahedral structures with the space group P 4 2c. In both compounds the cations are statistically distributed together with vacancies. The number of vacancies is estimated from the crystal structure analyses and results to be (Cu 0.54(2) In 1.15(2)□0.30(2) ) Se 2 for the δ‐phase and (Cu 0.36 In 1.09□0.55 ) (Se 1.80□0.20 ) for the Cu‐poor β‐phase.