The PtX_n Coordination Polyhedra (X = S, Se, Te) in Crystal Structures

摘要

Using the Voronoi-Dirichlet partition procedure and the method of intersecting spheres, it is demonstrated that in the crystal structures of chalcogen-containing compounds, Pt(IV) atoms form only PtX_6 octahedra (X = S, Se, Te), whereas in the case of Pt(III) and Pt(II), square coordination by X atoms is typical. The Pt(II) atoms can also form PtX_5 square pyramids (X = S, Se), PtS_6 octahedra, and PtTe_3Pt_3 quasi-octahedra in which a platinum atom is located in the trans-position to each coordinated tellurium atom. It was found that Pt(II) atoms in the PtX_4 squares (X=S, Se), unlike square-coordinated Pt(III) atoms, can form one or two Pt-M bonds (M is a d metal) and 1 to 4 secondary Pt-Q bonds, where Q is an s metal or hydrogen. The main features of platunum stereochemistry depending on the metal valence state and coordiantion number (CN) and on the nature of the chalcogen atom were quantitatively characterized in terms of the Voronoi-Dirichlet polyhedra.