Superconductivity mechanism in metal oxides with variable valency

In the present paper it is shown, that the metals with the mixed valency can have the subsystem of the local electron pairs. The local pairs may appreciably change the optical elastic modulus and the lattice parameters. The additions to the elastic modulus and the lattice parameters depend on concentration of the local pairs and temperature. The peculiarity of these dependences is the extrema. The concentration and temperature dependences of the additions are determined by intercentre correlations and pair delocalisation (pair transfer) in the subsystem of the local pairs. These results were used for the construction of the high-temperature superconductivity mechanism for the metals with the mixed valency