Crystal structures of the ScAgSe2 and Sc1.02Cu0.54Sn1.1S4 compounds

The crystal structures of the compounds ScAgSe2 (space group P3¯m1, a = 0.38779 (2) nm, с = 0.66501 (5) nm, Pearson symbol hP4, RI = 0.0679) and Sc1.02Cu0.54Sn1.1S4 (space group Fd3¯m, a = 1.04176 (6) nm, Pearson symbol cF53.28, RI = 0.0624) were determined by means of X-ray powder diffraction. The Se atoms in the structure of the ScAgSe2 compound are stacked in a close-packed arrangement with the layers in the sequence AB. The Sc atoms occupy half of the octahedral interstices, the Ag atoms occupy remaining octahedral interstices. The S atoms of the Sc1.02Cu0.54Sn1.1S4 compound are stacked in a close-packed arrangement with the layers in the sequence ABC. The atoms of Sc and statistical mixture M (Sc + Sn) are located in all octahedral interstices, the Cu atoms in 1/8 of the tetrahedral interstices.