Abstract
The phonon dispersion relations of K2ZnF4 are analyzed by lattice dynamical rigid ion and shell model calculations. It is shown that the concept of crystal‐independent interionic potentials is applicable for this non‐cubic substance. There is a structural unit in the tetragonal perovskitetype layer material K2ZnF4 in common with the cubic perovskite KZnF3, namely the ZnF6 octahedra. The influence of the crystalline environment on the lattice dynamical behaviour of this structural unit is studied by comparison of the phonon dispersion relations of both materials.