ANION DISORDER IN THE 115-118 K STRUCTURES OF THE ORGANIC SUPERCONDUCTORS KAPPA(L)-(BEDT-TTF)(2)CU(CF3)(4)(C2H3CL3) AND KAPPA(L)-(BEDT-TTF)(2)AG(CF3)(4)(C2H3CL3) [BEDT-TTF=3,4-3',4'-BIS(ETHYLENEDITHIO)-2,2',5,5'-TETRATHIAFULVALENE]

The low-temperature structures of the isostructural organic superconductors kappa(L)-(BEDT-TTF)(2)-Cu(CF3)(4)TCE, 5,5',6,6'-tetrahydro-2,2'-bis{1,3-dithiolo-[4,5-b][1,4]dithiin}ylidene tetra(trifluoromethyl)copper trichloroethane (1) (transition temperature, T-c = 4K), and kappa(L)-(BEDT-TTF)(2)Ag(CF3)(4)TCE, 5,5',6,6'-tetrahydro-2,2'-bis{1,3-dithiolo[4,5-b][1,4]dithiin}ylidene tetra(trifluoromethyl)silver trichloroethane (2) (T-c = 2.6K), contain crystallographically disordered anions and 1,1,2-trichloroethane (TCE) solvent molecules. Each entity is described as a mirror-symmetric superposition of two asymmetric components. The extent of anion disorder is extraordinary for an organic superconductor. Crystal data: (1) 2C(10)H(8)S(8).CuC4F12.C2H3Cl3, M(r) = 1242.28, orthorhombic, T = 118K, a = 12.918(4), b = 37.899(7), c = 8.487(2)Angstrom, V = 4155.1(18)Angstrom(3), Pnma (D-2h(16), NO. 62), Z = 4, F(000) = 2486, D-x = 1.986 Mg m(-3), mu(Mo K alpha) = 15.74 cm(-1), R = 0.051, wR = 0.039 for 3572 independent reflections with I > 2 sigma(1); (2) 2C(10)H(8)S(8).AgC4F12.C2H3Cl3, M(r) 1286.61, orthorhombic, T = 115 K, a = 12.936(4), b = 37.976(8), c = 8.526(2)Angstrom V = 4188.4(18)Angstrom(3), Pnma (D-2h(16), NO. 62), Z = 4, F(000) = 2553, D-x = 2.040 Mg m(-3) mu(Mo K alpha)= 15.16 cm(-1), R = 0.050, wR = 0.048 for 4022 independent reflections with I > 2 sigma(I).