Structure and electrical conductivity of (BEDT-TTF)2HgCl3·TCE

A new BEDT-TTF (BEDT-TTF=Bis(ethylenedithio)tetrathiafulvalene)-based cation radical salt (BEDT-TTF)2HgCl3·TCE (TCE=1,1,2-trichloroethane) was synthesized by using oxidative electro-crystallization at a constant current. Its structure was determined by four-circle X-ray diffraction method. The crystal belongs to monoclinic system, C2 space group with the unit cell parameters of a=39.236(5) Å, b=6.676(1) Å, c=14.881(3) Å, β=95.58(2)0, V=3879.4(12) Å3, Z=4. The structure 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 along the b-axis. The one-dimensional polymer (HgCl3)nn−, together with neutral TCE molecules, is also along the b-axis. Cationic BEDT-TTF sheets and anionic HgCl3− sheets are sandwiched along the a-axis. The room temperature resistivity of the single crystal was measured to be 3.33 Ω·m on the bc-plane. Its resistivity–temperature curve demonstrates a semiconductor behavior with an activation energy of 0.308 eV.