SUPERCONDUCTORS, METALS AND MAGNETS - STRUCTURE-PROPERTY RELATIONS IN MOLECULAR CHARGE-TRANSFER SALTS

The broad class of molecular charge transfer salts D(m)X(n)S(p) where D is a conjugated electron donor molecule that forms cations in the solid state, X is an inorganic anion and S a solvent molecule, encompasses the gamut of physical properties from superconductors to low-dimensional magnets, spin-Peierls systems and metal-insulator transitions as functions of pressure and temperature. The many structure types of salts with D = BEDT-TFF {bis(ethylenedithio)-tetrahiafulvalene} and X ranging from monoatomic halide to large heteropoly-cluster ions are surveyed in the overall context of crystals as ''chemically constructed multilayers'', with special reference to the simultaneous presence of localized and conduction electrons.