Home Crystal structure, electronic absorption spectra, and crystal field superposition model analysis of Li2Co3(SeO3)4
Article
Licensed
Unlicensed Requires Authentication

Crystal structure, electronic absorption spectra, and crystal field superposition model analysis of Li2Co3(SeO3)4

Published/Copyright: July 28, 2010

Abstract

Single crystals of the new compound Li2Co3(SeO3)4 have been synthesized under low-hydrothermal conditions. The structure was determined by direct methods from single crystal X-ray diffraction data (monoclinic, space group P21/c, a = 8.095(2) Å, b = 9.236(3) Å, c = 7.781(2) Å, β = 115.76(1)°, V = 523.9 Å3, Z = 2; R1 = 0.034 for 1613 Fo > 4σ(Fo) and 98 variables). Li2Co3(SeO3)4 builds a framework structure composed of one type of [4 + 2] coordinated Li atoms and each two crystallographically different CoO6 octahedra and pyramidal SeO3 groups. The polyhedra of lithium and of one type of the cobalt atoms exhibit uncommonly strong irregular distortions.

Polarized electronic absorption spectra of Li2CO3(SeO3)4 from 35000 to 4000 cm−1 were obtained by microscope-spectrometric techniques. The spectra were evaluated in terms of crystal field superposition model calculations for both triclinic Co2+ sites giving the first complete set of superposition model parameters for Co2+, i.e. the intrinsic parameters [unk]2 = 7000 cm−1 and [unk]4 = 4740 cm−1, and the power-law exponents t2 = 5.5 and t4 = 3.1. The interelectronic repulsion parameters are Racah B = 805 cm−1 and Racah C = 3630 cm−1. As already observed for several other selenite compounds, the derived crystal field strength parameters Dqcub again indicate a rather low position of the [SeO3]2− anion within the range of oxygen-based ligands in the spectrochemical series.

Published Online: 2010-7-28
Published in Print: 1999-4-1

© 2015 Oldenbourg Wissenschaftsverlag GmbH, Rosenheimer Str. 145, 81671 München

Downloaded on 24.9.2025 from https://www.degruyterbrill.com/document/doi/10.1524/zkri.1999.214.4.216/html
Scroll to top button