Is Tl2Ni3S2 a mixed valent compound? Crystal and electronic structure investigations

• Published in: Solid state sciences 2011-02, Vol.13 (2), p.337-343
• Main Authors: BACHHUBER, F, ANUSCA, I, ROTHBALLER, J, PIELNHOFER, F, PETER, P, WEIHRICH, R
• Format: Article
• Language: English
• Subjects: Bonding; Charge; Charge density; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Crystal structure; Electron density of states and band structure of crystalline solids; Electron states; Electronic structure; Exact sciences and technology; Flux; Mathematical analysis; Methods of electronic structure calculations; Physics; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; X-rays
• ISSN: 1293-2558; 1873-3085
• DOI: 10.1016/j.solidstatesciences.2010.11.032

The crystal and electronic structure of Tl2Ni3S2 is investigated by X-ray structure determination and DFT calculations. The question of charges and possible mixed valences of two different Tl positions in Tl2Ni3S2 is discussed with respect to crystal and electronic structure arguments. Crystal structure parameters were redetermined from single crystal data. A relation is given to typical Tl states in reference compounds like mixed valent Tl2S2, high-pressure TlS, LiTl, and ThCr2Si2 type TlNi2S2. This allows for a comparison of different Tl sites with respect to atomic distances, coordinations, valence, charge, and bonding as well as charge redistribution within layered Ni-S substructures. Complementary methods of charge determination from theory are applied as orbital analysis from precise full potential calculations and charge density analysis by zero flux surface integration according to the AIM theory. Can charge and valence of Tl be determined by comparison from different coordination spheres and electronic structure calculations? Tl sites in Tl2Ni3S2 are compared to related compounds including mixed valent Tl2S2. Display Omitted