EuCuOSe: Crystal structure refinement, electrical and magnetic properties

The europium copper oxyselenide EuCuOSe has been prepared by reacting Eu, CuO and Se in the ratio 1:1:1 at 1123 K for a period of 10 days in sealed quartz ampoule. The structure has been determined by single-crystal X-ray methods. The compound crystallizes tetragonal in the space group P4/nmm (no. 129) with two formula units in the cell with dimensions a = 393.65(8) pm and c = 871.80(17) pm. The structure is composed of {[(Eu3+)(O2−)4/4(Se2−)4/4]−}∞2 double layers separated by copper atoms, which are tetrahedrally coordinated to Se2− anions. According to the resistivity measurements, EuCuOSe is a semiconductor. The magnetic susceptibility data shows the typical non-Curie-Weiss behavior of the 7FJ states of Eu in the 4f6 configuration.