Structures and magnetic properties of some metal (I) chromium (III) sulfides and selenides

The crystal structures of M1CrX2(M = Na, Cu, Ag; X = S, Se) have been determined. The structures of CuCrX2 and AgCrX2 differ from those reported in literature. The susceptibility has been measured between 4 and 800°K. The compounds are antiferromagnetic with Néel temperatures between 19 and 50°K. Ferromagnetic interactions in the chromium layers occur in NaCrS2, NaCrSe2 and AgCrSe2. NaCrS2 probably has a helical spin structure.