Crystal structure of the new thorium intermetallics Thin and Th6Cd7

The title phases are orthorhombic: ThIn,oP24, space groupPbcm,a = 10.806(3)A?,b = 9.954(4)A?,c = 6.520(4)A?,Z = 12; Th₆Cd₇,oP26, space groupPbam,a = 11.703(3),A?,b = 9.929(7)A?,c = 6.041(2)A?,Z = 2. Direct methods were used for both structure solutions on data collected with an automated single crystal X-ray diffractometer. Anisotropic refinements gaveR = 0.065for ThIn andR = 0.086for Th₆Cd₇ using 799 and 1015 reflections, respectively. The structure of ThIn is closely related to the hexagonal Ti₅Ga₄ type, from which it can be geometrically derived. Th₆Cd₇ can be regarded as a tetrahedrally close packed structure where the Th atoms present the typical CN 14, CN 15, and CN 16 Frank-Kasper polyhedra and the Cd atoms are icosahedrally coordinated.