Currently the question naturally arises as to the effect of dimensional confinement on the properties on the phonons in ionic nanostructures as well as the properties of the phonon interactions in such nanostructures [1]. In the given work by Ewald’s method was calculated the Coulomb field in dipole lattice with zincblende structure. Thus, the previously developed covalent molecular-dynamic Valence Force Field model [2,3] was supplemented by Coulomb interactions between ions. This allowed to describe theoretically phonon dispersion dependences of nanodimensional slabs from GaP. In the work we consider a crystal slab consisting of N one-cell layers, parallel to the (hkl) plane of the crystal structure [4]. By appropriate choice of the unit cell, the primitive translation vectors 1 a and 2 a can be taken to lie on the (hkl) plane, while 3 a lies out of it. The slab is considered as a two-dimensional periodic structure and a two-dimensional reciprocal lattice is associated with it. The field at a point x due to all point dipoles p(l ', k ') at lattice sites x(l ', k ') , 1 2 3 l '  (l ', l ', l ') , is given byformulawhere ,  (1,2,3) number the axis of some Cartesian coordinate system 1 2 3 Ox x x , k ' runs over all ions in the unit cell, l ' runs over all unit cells from (,,0) to (,,N) , and q is a two-dimensional wave vector. We note that the index 3 l labels the one-unit-cell layers of the slab. Hence the index 3 (l , k) labels the atoms in the long unit cell of the two-dimensional periodic structure defined by the vectors 1 2 3 (a ,a ,Na ) . The sum over 1 2 l ', l ' on the right-hand side of Eq. (1) is a periodic function in two dimensions and can be expanded in Fourier seriesformulawhere 1 2 | | a s  a a and 1 2 K(h ,h ) is a vector of the two-dimensional reciprocal lattice. Further necessary to introduce a dividing point R on the  axis and evaluate the integral in Eq. (1) separately over the interval (0,R) using the right-hand side of relation (2) and over the interval (R,) keeping the integrand as it is. So twodimensional variant of Ewald’s method provides convergence of lattice sums in the case of ionic planar nanostructures. The described theoretical method allowed to carry out the lattice dynamics research of nanostructured ionic quasi-two-dimensional compounds and calculate energy spectra of such compounds from gallium phosphide in order to determine further their kinetic coefficients.