Ta5Se1.2Te1.8 - A tetrahedrally close-packed metal-rich layer structure

Article abstract of DOI:10.1002/zaac.199762301117

Ta₅Se_1.2Te_1.8 was prepared by reducing a mixture of TaSe₂ and TaTe₂ with tantalum at 1540°C. A X-ray single crystal structure analysis was performed. Space group: P1, a = 1008.5(4) pm, b = 1052.1(4) pm, c = 1440.2(5) pm, α = 90.32(2)°, β = 96.42(2)°, γ = 108.28(2), Z = 8, Pearson-Symbol: aP64, 5684 reflexions, 300 variables, R₁ = 0.066. The structure is built up of hetero-nuclear, distorted icosahedral clusters penetrating mutually into pentagonal anti-prismatic columns. The connection of these units by inter-columnar Ta-Ta-and Ta-Se,Te-contacts affords tetrahedral close-packed layers. The chalcogen atoms are one-sidedly coordinated by three, four or six tantalum atoms.