A model for the description of the lattice structure dynamics and elastic properties of the La2CuO4crystal, including the Jahn-Teller contribution to the energy and dynamic matrix of the crystal have been developed. Dielectric constants, elastic modula and phonon frequencies in Γ and X points of the Brillouin zone, and also soft-mode behaviour depending on the hydrostatic pressure for La2NiO4and La2CuO4have been calculated. © 1996, R. Oldenbourg Verlag, München 1997. All rights reserved.