STRUCTURES OF 2 BIS(ETHYLENEDITHIO)TETRATHIAFULVALENE HEXAMOLYBDATE AND HEXATUNGSTATE SALTS - (BEDT-TTF)2MO6O19, (BEDT-TTF)2W6O19

2C10H8S8+.Mo6O19(2-) (1), M(r) = 1649, monoclinic, P2(1)/c, a = 8.898 (8), b = 11.265 (4), c = 21.098 (8) angstrom, beta = 96.34 (5)degrees, V = 2102 angstrom-3, Z = 2, D(x) = 2.605 g cm-3, F(000) = 1592, lambda(Mo K-alpha) = 0.71073 angstrom, mu = 25.33 cm-1, T = 293 K, R = 0.036 based on 1527 observed reflections with I greater-than-or-equal-to 3-sigma(I). 2C10H8S8+.W6O19(2-) (2), M(r) = 2176.46, monoclinic, P2(1)/c, a = 8.908 (7), b = 11.310 (5), c = 21.111 (8) angstrom, beta = 96.37 (7)degrees, V = 2113.8 angstrom-3, Z = 2, D(x) = 3.419 g cm-3. Only the structure of (1) has been determined since the two compounds are isostructural. The central C = C (1.388 angstrom) and the two types of C--S (average 1.720 and 1.737 angstrom) bond lengths of the BEDT-TTF molecule compare well with those observed for one which is fully oxidized. As in the kappa-(BEDT-TTF)2X salts, the organic radical cations form orthogonalized dimers (dihedral angle 76-degrees). Short intra-dimer (Sl...S4 3.551 and S2...S3 3.553 angstrom) and inter-dimer (S7...S8 3.508 angstrom) S...S contacts are observed. The crystal structure is built by alternating ABABA... organic and inorganic layers along the [100] direction.