Structures and Physical Properties of New β′-BEDT-TTF Tris-Oxalatometallate (III) Salts Containing Chlorobenzene and Halomethane Guest Molecules

We report the structures and physical properties of new β′-(BEDT-TTF) 4[Fe(oxalate) 3]·G salts where A = H 3O +, G = PhCl; A = Rb + G = Pyridine. The structure of the PhCl salt is isomorphous with β′-(BEDT-TTF) 4[(H 3O)M(oxalate) 3] with other guest molecules. PhCl is ordered in die hexagonal pockets formed by the [(H 3O)Fe(oxalate) 3] layer. The electrical conductivity is metallic down to 100 K, below which the resistivity increases with decreasing temperature. The specific conductivity at room temperature is about 10 S/cm. We also report the salt β′-(BEDT-TTF) 4[RbFe(oxalate) 3]·Pyridine where Rb + replaces H 3O. The electrical resistivity shows metallic behavior down to 100 K. and turns up gradually to a maximum at 65 K below which the system re-enters the metallic state down to liquid helium temperature. Neither salt shows superconductivity down to 2 K. In addition, other new β′-(BEDT-TTF) 4[(H 3O)M(oxalate) 3]·salts with M = Cr, Ga, Fe; G = CH 2Cl 2, CH 2ClBr, CH 2Br 2 are also reported.