In the MxPS3 and M1-xMx'PS3 systems, the P2S6 cluster contributes to the poor electrical conductivity for the compounds in which the energy level of the metal 3d orbital is deeper than those of the P, S 3p orbitals. For the compounds in which metal 3d orbital is closed to P and S 3p orbitals and has mixed valency, the induced mixed valency of P2S6 cluster and/or hopping mechanism contribute to the electrical conductivity. In the organic electron donor intercalation into MxPS3 and M1-xMx'PS3 compounds, the new intercalation reaction is dis covered, in which formation of tris-complexes of metal ions with guest molecules occurs in the host interlayer.