Metal-Rich Chalcogenides. Synthesis, Structure, and Bonding of the Layered Lu₁₁Te₄. Comparison with the Similar Sc₈Te₃ and Ti₁₁Se₄

The high-yield synthesis of Lu₁₁Te₄ by reaction of the components and annealing at 1200 °C is described. The structure determined by single-crystal diffraction means is monoclinic C2/m, Z = 6, a = 30.412(3) Å, b = 3.9504(4) Å, c = 21.073(2) Å, β = 102.96° and consists of two independent condensed puckered sheets of Lu separated by individual Te atoms. Notwithstanding, the geometric structure is closely related to but distinctly different from those of both Sc₈Te₃ and Ti₁₁Se₄ (also C2/m), principally through displacements of pairs of atoms (the structure of the last was determined by electron diffraction). Further, close electronic similarities among the three structures are demonstrated by EHTB results in terms of both effective atom charge and bond overlap population trends between equivalent positions or functions.