CHEMICAL-BOND PROPERTIES OF RARE-EARTH IONS IN CRYSTALS

By using the dielectric description theory of ionicity of solids, chem ical bond properties of rare earth ions with various ligands are studi ed. Calculated results show that chemical bond properties of the same rare earth ion and the same ligand in different crystals depend on the crystal structures. In a series of compounds, chemical bond propertie s of crystals containing different rare earth ions are similar. The ma gnitude of covalency of chemical bonds of trivalent rare earth ions an d various ligands has an order like F<Cl<Br<As<Sb. (C) 1998 Elsevier S cience S.A.