STRUCTURE OF 1,2-DIPHENYLCARBABORANE, 1,2-PH2-1,2-CLOSO-C2B10H10

1,2-Diphenyl-1,2-dicarba-closo-dodecaborane(12), C14H20B10, M(r) = 296 .41, monoclinic, P2(1)/c, a = 10.832 (4), b = 24.890 (13), c = 13.9243 (21) angstrom, beta = 111.881 (21)degrees, V = 3483.6 angstrom3, Z = 8, D(x) = 1. 130 Mg m-3, lambda(Mo Kalpha) = 0.71069 angstrom, mu = 0. 051 mm-1, F(000) = 1232, T = 291 (1) K, R = 0.0703 for 3779 independen t observed reflections. The C2B10 fragments of the two crystallographi cally independent molecules are practically superimposable (r.m.s. mis fit 0.013 angstrom), but the phenyl rings of molecule B are slightly t wisted (in a conrotatory manner) relative to those in molecule A. In g eneral terms, however, the phenyl rings in both molecules lie roughly perpendicular to the plane through the atomic sequence C(aryl)-C(cage) -C(cage)-C(aryl). The C(cage)-C(cage) distance is 1.733 (4) angstrom i n molecule A and 1.720 (4) angstrom in molecule B.