Crystal structure and properties of K2[OsO2(C2O4)2] • 2H2O

The compound crystallizes in the triclinic crystal system, space group P $(1) over bar $, angstrom, b = 6.835(2) angstrom, c = 7.595(2) angstrom, alpha = 85.76(2)degrees, beta = 65.33(2)degrees, gamma = 71.14(2)degrees, and Z = 1. The osmium atom is located at the center of symmetry and has a distorted octahedral coordination formed by oxygen atoms: two oxygen atoms of the osmyl group occupy the apical positions [Os-O, 1.730(2) angstrom], and four oxygen atoms of the oxalate ions lie in the equatorial plane. The K+ cation is surrounded by ten oxygen atoms located at different K-O distances in the range from 2.787(2) to 3.158(2) angstrom. The assignment of the absorption bands in the IR spectrum of K-2[OsO2(C2O4)(2)]center dot 2H(2)O is performed. The electronic absorption spectra of the compound are recorded in different solvents, and the thermal behavior in air is studied.