Sc2Te5O13 und Sc2TeO6: Die ersten Oxotellurate des Scandiums

Abstract Sc2Te5O13 and Sc2TeO6: The First Oxotellurates of Scandium Sc2Te5O13 and Sc2TeO6 are the first oxotellurates of scandium that could be structurally elucidated by X‐ray diffraction using single crystals. The scandium(III) oxotellurate(IV) Sc2Te5O13 was synthesized by reacting Sc2O3 with TeO2 at 850 °C and crystallizes in the triclinic system with space group (no. 2) and the lattice parameters a = 660.67(5), b = 855.28(7), c = 1041.10(9) pm, α = 86.732(8), β = 86.264(8), and γ = 74.021(8)° (Z = 2). The crystal structure contains chains respectively strands of alternatingly edge‐ and vertex‐sharing [ScO6]9− and [ScO7]11− polyhedra. These strands are connected by [TeO3+1](2+2)− oxotellurate(IV) anions. The coordination spheres of Sc3+ appear markedly smaller than those of M3+ cations in the other known compounds of the formula type M2Te5O13 (M = Y, Dy – Lu), therefore Sc2Te5O13 is not really isotypic, but only isopuntal with these compounds. Single crystals of the scandium(III) oxotellurate(VI) Sc2TeO6 were obtained through the fusion of a mixture of Sc2O3 and TeO3 at 850 °C. It crystallizes trigonally (a = 874.06(7), c = 479.85(4) pm and c/a = 0.549) with the Na2SiF6‐type structure in space group P321 (no. 150) and three formula units per unit cell. Its crystal structure is built up by a hexagonal closest packing (hcp) of oxide anions with the Sc3+ cations residing in 1/3 and the Te6+ cations in 1/6 of the octahedral interstices in a well‐ordered occupation pattern. Thus one can address the structural situation in Sc2[TeO6] as a stuffed β‐WCl6‐type arrangement.