STRUCTURE OF TRIS(PHENYLSELENO)PHOSPHINE

C18H15PSe3, M(r) = 499.17, trigonal (hexagonal cell), R3BAR, a = 12.8896 (5), c = 19.1855 (7) angstrom, V = 2760.5 (2) angstrom3, Z = 6, D(x) = 1.80 g cm-3, lambda(Mo Kalpha) = 0.71069 angstrom (graphite monochromator), mu = 60.16 cm-1, F(000) = 1440, T = 296 K, R = 0.068 for 998 observed reflections with I > 3sigma(I). The structure determination provides the first crystallographic data of the strain-free P(SeCR)3 unit. Distances: P-Se 2.271 (2), Se-C 1.925 (6) angstrom; angles: Se-P-Se 96.6 (1), P-Se-C 97.6 (2)-degrees. The individual molecules have crystallographically imposed threefold symmetry and pack in layers, possibly giving the structure applications in intercalation chemistry.