X-ray Rietveld structure refinement and bond-valence analysis of Cs₂TeI₆

Chem. Met. Alloys 3 (2010) 108-114

https://doi.org/10.30970/cma3.0127

V.I. SIDEY, O.V. ZUBAKA, I.P. STERCHO, E.Yu. PERESH

The crystal structure of the ternary iodide Cs₂TeI₆ has been refined by Rietveld analysis of X‑ray powder diffraction data. The refinement procedure was stopped when the intensity residual R_B = 3.7 % had been reached. Cs₂TeI₆ crystallizes in the cubic K₂PtCl₆ structure type, space group Fm-3m (No. 225), with the lattice parameter a = 11.6939(8) Å, Z = 4, D_c = 4.797(1) g/cm³. The reliability of the structural model obtained for Cs₂TeI₆ in the Rietveld refinement was confirmed by a bond-valence analysis of the structure. For the first time, the bond-valence parameters (r₀ = 2.782 Å and b = 0.37 Å) have been determined for the Te⁴⁺/I^– ion pair, from a set of 14 well-determined coordination shells [TeI_n]. These parameters show a reasonably high performance and can be recommended for routine bond-valence analyses of structures containing Te⁴⁺–I^– chemical bonds.

Crystal structure of K₂PtCl₆: [PtCl₆] coordination octahedra and K atoms.

Keywords

Ternary halides / Crystal structure / Bond-valence model