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

 

Chem. Met. Alloys 3 (2010) 108-114

 

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 RB = 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, Dc = 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+/IЦ ion pair, from a set of 14 well-determined coordination shells [TeIn]. These parameters show a reasonably high performance and can be recommended for routine bond-valence analyses of structures containing Te4+ЦIЦ chemical bonds.

 

 

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

 

Keywords

Ternary halides / Crystal structure / Bond-valence model