Superconductivity in a new family of organic conductors

Evidence for superconductivity in (BEDT-TTE)4(ReO4)2 [where BEDT-TTF is bis (ethylenedithiolo)tetrathiafulvalene] near 2 K for pressures above 4 kbar is reported. This is the first unambiguous observation of superconductivity in a sulfur-donor organic system. At higher pressures the transition temperature decreases rapidly, dTcdP∼-0.3 K/kbar. At low pressures this material exhibits a first-order metal-insulator transition, postulated to result from a change in the arrangement of the anions which are ordered at room temperature. © 1983 The American Physical Society.