| Abstrakt: |
Synthesis, structural characterization and chemical bonding peculiarities of two new quaternary selenides of the Tl4Sb8Sn5Se24and Tl5Sb2Sn4Se14−x(x = 0.5) are reported. The crystal structures of these compounds were determined by single crystal X-ray diffraction analysis. The Tl4Sb8Sn5Se24phase is a new structure type and crystallizes in the triclinic P1̅ space group (a = 7.9061(13) Å, b = 13.9035(16) Å, c = 21.4665(17) Å, α = 80.058(8)°, β = 84.727(10)°, γ = 73.542(12)°, wR2= 0.0258, 8200 F2values, 373 variables). The Tl5Sb2Sn4Se14−x(x = 0.5) phase represents a new structure type with a tetragonal unit cell (P4/mbm, a = 8.1570(10) Å, c = 21.946(3) Å, wR2= 0.0346, 1953 F2values, 44 variables). Crystallographic analysis together with linear muffin-tin orbital band structure calculations reveals that both structures we conform to the concept of Zintl-Klemm and exhibit semiconductor properties. |
