Crystal and electronic structure of the ternary monoclinic selenide Tl2.59Sb8.41Se14 (TlSb3Se5)

 

Chem. Met. Alloys 9 (2016) 11-20

 

Ihor BARCHIY, Anatoliy TATZKAR, Marian SABOV, Ewa ROŻYCKA-SOKOŁOWSKA, Bernard MARCINIAK, Volodymyr PAVLYUK

 

The ternary selenide Tl2.59Sb8.41Se14 crystallizes with a monoclinic structure in space group P21/m where the atoms are located on 2e sites (site symmetry m). The structure of the title compound is closely related to the strongly disordered structure of K2.5Sb8.5Se14. The coordination polyhedra of the thallium atoms are trigonal prisms with additional selenium atoms centering lateral faces. All the antimony atoms are coordinated by slightly deformed Se6 octahedra. Three types of polyhedron: octahedron, trigonal bipyramid and tetrahedron, are observed for the selenium atoms. The crystal chemical analysis and electronic structure calculations by the TB-LMTO-ASA method show that the antimony and selenium atoms form a polyanionic network the negative charge of which is compensated by the thallium cations.

 



 

Polyanionic 3D-network of selenium and antimony atoms.

 

Keywords

Selenide / Crystal structure / Electronic structure