Abstract
The κ-(BEDT-TTF)2X salts (BEDT-TTF ≡ bis(ethylenedithio)tetrathiafulvalene) are classified as strongly correlated electron systems. Therefore the electronic structure is calculated on the basis of the tight-binding approach previously developed for correlated electrons. It is shown that intradimer electron interactions provide the insulating state of system. An insulator-metal phase transition of Mott-Hubbard kind is derived. Based on the electronic band symmetry in metallic state, the anisotropic superconducting pairing of different symmetries is studied. The results obtained are in agreement with available experimental data and theoretical speculations.