Structure and electrical conductivity of (BEDT-TTF)2HgCl(3) center dot TCE

A new BEDT-TTF (BEDT-TTF = Bis(ethylenedithio)tetrathiafulvalene)-based cat ion radical salt (BEDT-TTF)(2)HgCl3. TCE (TCE = 1,1,2-trichloroethane) was synthesized by using oxidative electro-crystallization at a constant curren t. Its structure was determined by four-circle X-ray diffraction method. Th e crystal belongs to monoclinic system, C2 space group with the unit cell p arameters of a = 39.236(5) Angstrom, b = 6.676(1) Angstrom, c = 14.881(3) A ngstrom, beta = 95.5X(2)degrees, V= 3879.4(12) Angstrom(3), Z= 4. The struc ture shows that the BEDT-TTF radicals are stacked to form columns along the c-axis and arranged side-by-side to form one-dimensional uniform chains al ong the b-axis. The one-dimensional polymer (HgCl3)(n)(n-), together with n eutral TCE molecules, is also along the b-axis. Cationic BEDT-TTF sheets an d anionic HgCl3- sheets are sandwiched along the a-axis. The room temperatu re resistivity of the single crystal was measured to be 3.33 Omega . m on t he be-plane. Its resistivity-temperature curve demonstrates a semiconductor behavior with an activation energy of 0.308 eV. (C) 2000 Elsevier Science S.A. All rights reserved.