The crystal structure of Th3B2C3

The crystal structure of Th3B2C3 has been determined by single crystal X-ray analysis. The lattice parameters of the monoclinic cell (first setting) are: a=3.703(2)A,b=9.146 (4)A,c=3.773(1)A and γ=100.06(7)0; space group:P2/m (C1sub(2h)), Z=1. Intensity measurements were obtained from a fourcircle diffractometer. The structure was solved by Patterson methods and refined by full matrix least squares calculation. For an asymmetric set of 401 independent reflexions the final R-value is 0.079. The structure contains octahedra, tetrahedra and trigonal prims of Th-atoms. The trigonal prisms are centered by boron atoms. Th-octahedra by carbon atoms C1;Carbon atoms C2 actually have octahedral coordination 5 Th + 1 B. The structural chemistry of Th3B2C3 with respect to the crystal structures of ThC and ThBC is discussed. (Auth.)