Materials with layered structures XI: X-ray powder diffraction investigations in the systems CuIn5S8-CuIn5Se8 and AgIn5S8-AgIn5Se822

The title systems have been investigated by powder X-ray diffraction methods on quenched samples. In the system CuIn5S8-xSex two new compounds with layered structures have been detected. Samples quenched from 800°C crystallise for 4 ≤ x ≤ 5 hexagonally with a = 395.81 and c = 3208.6 pm (x = 4) while samples quenched from 650°C for 6 ≤ x < 7 are hexagonal as well but with a = 399.57 and c = 1615.5 pm (x = 6). In the system AgIn5S8-xSex no compound crystallising in a layered structure is obtained. AgIn5S0.8Se7.2 crystallises in a Wurtzite like structure with a = 408.4 and c = 667.0 pm. The spinel type phases CuIn5S8-xSex and AgIn5S8-xSex are stable up to x < 2 (800°C) and x ≤ 5.6 (700°C), respectively. The silver containing spinels decompose above 800°C into two spinel type compounds. At 1000°C this decomposition is observed for 2.4 ≤ x ≤ 5.6.