On Polychalcogenides of Thallium with M2 Q11 Groups as a Structural Building Block. II. Tl4Ta2Se11: Synthesis,Crystal Structure,Properties and Spectroscopic Investigations of the First Polyselenide being Composed of a Discrete [Ta2Se11]4— Anion |
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Authors: | Christoph L Teske Nicolai Lehnert Wolfgang Bensch |
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Abstract: | The new ternary compound Tl4Ta2Se11 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)°. Tl4Ta2Se11 is the first polyselenide with discrete complex M2Se11]4— anions. Every Ta atom is in a sevenfold environment of Se atoms to form a distorted pentagonal bi‐pyramid. The two TaSe7 polyhedra have a face in common thus yielding the Ta2Se11]4— unit. In the structure, the anions are well separated by the Tl1+ cations. An assignment of the different vibration modes in the IR and Raman spectra is given based on density functional calculations. |
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Keywords: | Polyselenide Thallium Tantalum Crystal structure Vibrational spectroscopy |
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