LAUSR

Crystallochemical analysis with the use of Voronoi–Dirichlet polyhedra (VDPs) has been performed for 711 sulfides, whose structures contain 1199 coordination polyhedra LnSn, where Ln is a lanthanide from La to Lu. It has been established that the sulfides incorporate Ln(II), Ln(III), and Ce(IV) atoms bonding from 6 to 10 sulfur atoms, which exist in the form of S2– or S– ions. The VDP parameters provide the possibility to determine the valence state of Ln atoms in the structures of sulfides and distinguish S2– or S– ions. The VDPs of 2913 sulfur atoms have been characterized to establish the dependence between the multiplicity of S–S bonds and their length. A quantitative estimate of lanthanide contraction in LnIIIXn polyhedra is given depending on the nature of chalcogen Х (O, S, Se, or Te).