Single crystals of two new phases Tl4 Re6 S12 and Tl4 Re6 Se12 isostructural with (Rb,K)4 Re6 Se12 were synthesized by high-temperature reaction of TlX, Re, and X (X = S, Se). The structure of the selenide was solved by single-crystal X-ray investigation (space group C2/c, R = 0.08). The structure consists of Re6 Se8 cluster units interconnected three-dimensionally by four Se and two Se2 bridges. Tl4 Re6 S12 is isostructural with Tl4 Re6 Sel2. The cell parameters of Tl4 Re6 S12 and Tl4 Re6 Se12 are a = 16.653 (2) Å, b = 9.574 (3) Å, c = 11.816 (8) Å, β = 90.62 (2)° and a = 17.177 (3) Å, b = 9.846 (2) Å, c = 12.195 (2) Å, β = 90.71 (2)°, respectively. Z = 4 for both compounds. Physical measurements show that these compounds are semiconducting and diamagnetic, which is consistent with 24 electrons per cluster unit filling the valence band. Bond-order calculations of Tl4 Re6 Se12 and other related compounds indicate a Re-Re bond order of 1 in all of the known Re6 X8 cluster compounds.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Inorganic Chemistry