Electron density and chemical bonding in tetragonal A2B 2 5 crystals. II. ZnP2 and CdP2

The electron density of tetragonal ZnP₂ and Cdh₂ has been calculated by the pseudopotential method. The valence band of ZnP₂ and CdP₂ consists of 48 subbands grouped into 4 subbands. The Zn(Cd)–P bond proved to be ionic-covalent, with a bond charge of 0.01(2)e whose maximum is shifted toward phosphorus. The (r) maximum of the shortest P1–P3 bond lies in its middle; the bond charge values are 0.25e (ZnP₂) and 0.50e (CdP₂). The charge maximum on the P₂–P₃ bond lies near the middle of the bond; it slightly deviates from the bond direction in the (P1, P2 P3) plane, indicating anisotropy of the bond. The partial electron densities have been calculated for the four subbands of the valence band. The reason for the splitting of the phosphorus s-band into two bands in ZnP₂ and CdP₂ was found to be sp-hybridization in the region of the s-band, which is the strongest for the shortest P1–P3 bond.Kemerovo State University. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 52–56, September–October, 1993.Translated by L. Smolina