CRYSTAL-STRUCTURE OF THBC

The crystal structure of ThBC has been determined by single crystal X-ray analysis. The lattice parameters of the tetragonal cell were found to be a = 3.762(2), c = 25.246(5) Å. The space group is P4122 (D43), Z = 8. Intensity measurements were made on a fourcircle diffractometer. The structure was solved by Patterson methods and refined by full matrix least squares calculation. R with isotropic temperature factors is 0.06 for 381 observed reflections. The structure contains tetrahedra and trigonal prisms of Th atoms. The trigonal prisms are centered by boron atoms, carbon atoms have octahedral coordination 5Th + 1B. The crystal structure of ThBC can be generated by a simple shift out of the UBC-type structure. The structural chemistry of ThBC, UBC and YBC is discussed. © 1978.