NEW ORGANIC SUPERCONDUCTOR BASED ON DEUTERATED BIS(ETHYLENEDITHIO)-TETRATHIAFULVALENE, KAPPA-(D(8)-ET)(4)(HGBR(2)CENTER-DOT-HG(2)BR(6))

The deuterated organic salt based on (d8-ET) (ET is bis(ethylenedithio ) tetrathiafulvalene (BEDT-TTF)) was synthesized with bromine-mercurat e anion. X-ray crystallographic studies have demonstrated it to have t he following formula, kappa-(d8-ET)4(HgBr2 . Hg2Br6). Various types of the temperature dependences of conductivity for the crystals from the same batch have been found but not one of the studied samples was a s uperconductor at ambient pressure. All crystals studied at ambient pre ssure seem to become superconductors at low pressure (approximately 30 0 bar) with different T(c). Crystal structure features of this salt wi th d8-ET cation are compared with the structure of an organic supercon ductor (ET)4Hg2.89Br8 at ambient pressure. The differences in their su perconducting properties are associated with high lability of Hg-conta ining salts.