On the properties of two-dimensional compounds AgX$_{2}$ (X=F, Cl, Br, I)

Analytical expressions are obtained for the electron and phonon spectra and the electron–phonon interaction of two-dimensional (2D) compounds MX$_2$, where M is a metal atom and X is a nonmetal atom, forming a 2D-CuO$_2$-type square lattice. Numerical estimates for the AgX$_2$ family showed that all considered characteristics of silver fluoride strongly differ from the characteristics of other AgX$_2$ compounds, but are close to the characteristics of 2D-CuO$_2$. It is shown that the superconducting transition temperature $T_c$(2D CuO$_2$)>$T_c$(2D AgF$_2$).