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On Polychalcogenides of Thallium with M 2 Q 11 Groups as a Structural Building Block. II. Tl 4 Ta 2 Se 11 : Synthesis, Crystal Structure, Properties and Spectroscopic Investigations of the First Polyselenide being Composed of a Discrete [Ta 2 Se 11 ] 4— Anion
Author(s) -
Teske Christoph L.,
Lehnert Nicolai,
Bensch Wolfgang
Publication year - 2002
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/1521-3749(200212)628:12<2651::aid-zaac2651>3.0.co;2-w
Subject(s) - triclinic crystal system , crystallography , chemistry , crystal structure , square pyramid , raman spectroscopy , stereochemistry , physics , optics
Abstract The new ternary compound Tl 4 Ta 2 Se 11 was prepared in a melt of thallium polyselenides applying elemental tantalum. It crystallises in the triclinic space group P1¯ with a = 7.996(1) Å, b = 9.866(1) Å, c = 13.668(2) Å, α = 73.03(1)°, β = 89.21(2)° and γ = 85.72(1)°. Tl 4 Ta 2 Se 11 is the first polyselenide with discrete complex [M 2 Se 11 ] 4— anions. Every Ta atom is in a sevenfold environment of Se atoms to form a distorted pentagonal bi‐pyramid. The two TaSe 7 polyhedra have a face in common thus yielding the [Ta 2 Se 11 ] 4— unit. In the structure, the anions are well separated by the Tl 1+ cations. An assignment of the different vibration modes in the IR and Raman spectra is given based on density functional calculations.