The synthesis and characterization of radical cation salts of bis(ethylenedithio)tetraselenafulvalene

Abstract

Four 2:1 radical cation salts (SbF6, CF3SO3, GaCl4, Cu[N(CN)2]Br) of bis(ethylenedithio)-tetraselenafulvalene (BETS) have been prepared and scrutinized by X-ray crystallography, DC resistivity measurements (300-10K), rf penetration depth experiments (0.5K), pressure studies (0.5–5kbar, 4K), and tight-binding band calculations. The salts are κ-phase, and three are metallic to low temperatures. κ-(BETS)2 Cu[N(CN)2]Br is isostructural with κ-(ET)2 Cu[N(CN)2]Br.