Polymorphism in (kappa)-(BEDT-TTF)(sub 2)M(CF(sub 3))(sub 4)(solvent) superconductors

摘要

A new crystallographic modification ((Kappa)(sub L)(sup ')) was found in the BEDT-TTF:M(CF(sub 3))(sub 4)(sup -): solvent (M=Cu, Ag, Au) system. The structure of monoclinic (Kappa)(sub L)(sup ')-(BEDT- TTF)(sub 2)Cu(CF(sub 3))(sub 4)(1,2-dibromo-1-chloroethane = DCBE) is reported. It differs from the orthorhombic (Kappa)(sub L)(sup ')- phase by having all BEDT-TTF molecules tilted in the same direction with respect to the conducting phase normal, whereas in (Kappa)(sub L) the tilt direction alternates between layers.