STRUCTURE REFINEMENTS OF ACTINOID TRANSITION-METAL STANNIDES ANT2-XSN2-Y (AN-EQUIVALENT-TO-TH, U T-EQUIVALENT-TO-CO, NI, CU) WITH DEFECT CABE2GE2-TYPE STRUCTURE

The crystal structures of the six title compounds were refined from si ngle-crystal X-ray data. At least one of the transition metal sites in each compound is not fully occupied. Partial occupancies were also fo und for most of the tin sites of these compounds and for all uranium c ompounds one tin site had to be refined with split atom positions. Thu s the compositions of these stannides may be written as ThCo1.50Sn1.96 , ThNi1.80Sn1.91, ThCu1.50Sn1.77, UCo1.41Sn1.85, UNi1.42Sn1.88 and UCu 1.30Sn1.91. The crystal structures are briefly discussed.