STRUCTURE OF TETRAETHYLAMMONIUM NONACARBONYL-MU-3-([DICHLORO(UNDECACARBONYL-COBALTIO)SILYL]OXYMETHYLIDYNE)-TRICOBALTATE, [ET4N][CL2SICO7(CO)21]

C29H20Cl2Co7NO21Si, M(r) = 1230.0, monoclinic, P2(1)'/c, a = 9.110 (4), b = 22.472 (9), c = 21.01 (1) angstrom, beta = 95.28 (4)-degrees, V = 4283 (3) angstrom3, Z = 4, D(x) = 1.91 g cm-3, lambda(Mo K-alpha) = 0.7107 angstrom, mu = 29 cm-1, F(000) = 2424, T = 148 K, R = 0.0555 for 2626 [I > 3-sigma(I)] reflections. The Si atom is bonded to two Cl atoms [Si-Cl (av.) = 2.094 (6) angstrom, Cl-Si-Cl = 101.7 (2)-degrees], to a Co4(CO)11 moiety [Si-Co = 2.209 (5) angstrom, Co-Si-Cl (av.) = 118.0 (3)-degrees], and to the O atom of a mu-3-CO group which bridges a Co3(CO)9 unit [Si-O = 1.67 (1), O-C = 1.32 (2) angstrom, O-Si-Cl(av.) = 102.9 (4), O-Si-Co = 111.1 (4)-degrees].