Stable molecular metals based on bis(ethylenedithio)tetraselenafulvalene and halogen ions: κ-(BETS)2X·C2H4(OH)2 (X=Br, Cl)

New stable molecular metals κ-(BETS)2X·C2H4(OH)2(X=Br− (1), Cl− (2)) (BETS=bis(ethylenedithio)tetraselenafulvalene) were prepared and their full X-ray studies were performed. The crystals of 1 and 2 are isostructural to each other. BETS molecules form the κ-type packing. The polymeric anion layers constructed of halogen atoms and ethylene glycol molecules included in the crystal have short contacts between halogen anions and oxygen atoms of the ethylene glycol molecules: Br⋯O, 3.27(2) Å; Cl⋯O, 3.22(3) Å. Temperature dependence of the electrical resistivities of 1 and 2 were metallic from room temperature down to 0.9 and 4.0 K, respectively.