Calculation of interplanar distances near the faces of ionic crystals with lattices of NaCl type and face-centered molecular crystals

Conclusions Interplanar distances near faces have been calculated for ideal ionic crystals of NaCl type and face-centered molecular crystals by successive approximation 4]. The repulsive forces for the ionic crystals were taken as br^–n, while the attractive and repulsive forces for the molecular crystals were taken asar^–m and br^–n, respectively. The numerical values fora and b were derived from the equilibrium conditions for an infinite crystal.We found that the difference between the interplanar distance and the lattice constant increased as n decreased for ionic crystals, the distance between the second and third planes being the largest.The above difference is positive for molecular crystals and decreases inwards; it is 5% of the lattice constant for the first and second planes but only 0.1% for the fifth and sixth.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 148–150, February, 1972.