Rich Structural Chemistry in Scandium Selenium/Tellurium Oxides: Mixed-Valent Selenite–Selenates, Sc2(SeO3)2(SeO4) and Sc2(TeO3)(SeO3)(SeO4), and Ternary Tellurite, Sc2(TeO3)3

Both single crystals and pure bulk phases of three new scandium selenium/tellurium oxides, Sc2(SeO3)2(SeO4), Sc2(TeO3)­(SeO3)­(SeO4), and Sc2(TeO3)3, have been synthesized through hydrothermal and solid-state reactions. X-ray diffractions were used to determine the structures and confirm the phase purities of the reported materials. Isostructural Sc2(SeO3)2(SeO4) and Sc2(TeO3)­(SeO3)­(SeO4) reveal three-dimensional frameworks with ScO7 pentagonal bipyramids, SeO3 (and TeO3) trigonal pyramids, and SeO4 tetrahedra. A novel ternary scandium tellurite, Sc2(TeO3)3, also shows a three-dimensional framework that is composed of ScO6 octahedra, ScO7-capped octahedra, and TeO3 trigonal pyramids. All three materials accommodate local asymmetric coordination moieties owing to the lone pairs on Se4+ and Te4+ cations. The effect of coordination environments of constituent cations on the frameworks, dimensionalities, and centricities of products is discussed. Thorough characterizations including elemental analyses, infrared and UV–vis diffuse reflectance spectroscopies, thermal analyses, and dipole moment calculations for the reported materials are reported. Crystal data: Sc2(SeO3)2(SeO4), monoclinic, space group P21/c (No. 14), a = 6.5294(2) Å, b = 10.8557(4) Å, c = 12.6281(6) Å, β = 103.543(3)°, V = 870.21(6) Å3, and Z = 4; Sc2(TeO3)­(SeO3)­(SeO4), monoclinic, space group P21/c (No. 14), a = 6.5345(12) Å, b = 10.970(2) Å, c = 12.559(2) Å, β = 102.699(10)°, V = 878.3(6) Å3, and Z = 4; Sc2(TeO3)3, monoclinic, space group P21/n (No. 14), a = 5.2345(3) Å, b = 24.3958(15) Å, c = 6.8636(4) Å, β = 106.948(2)°, V = 838.42(9) Å3, and Z = 4.本研究通过水热法与固相反应，成功制备出三种新型硒/碲氧化钪单晶与纯相块体材料，其化学式分别为Sc₂(SeO₃)₂(SeO₄)、Sc₂(TeO₃)(SeO₃)(SeO₄)与Sc₂(TeO₃)₃。采用X射线衍射技术对所制备材料的晶体结构进行解析，并验证其相纯度。同构的Sc₂(SeO₃)₂(SeO₄)与Sc₂(TeO₃)(SeO₃)(SeO₄)均呈现三维骨架结构，其结构基元包括ScO₇五角双锥、SeO₃（及TeO₃）三角锥与SeO₄四面体。新型三元亚碲酸钪Sc₂(TeO₃)₃同样具有三维骨架结构，其结构由ScO₆八面体、ScO₇盖帽八面体以及TeO₃三角锥构成。由于Se⁴⁺与Te⁴⁺阳离子存在孤对电子，三种材料均具有局域不对称配位结构基元。本文讨论了组成阳离子的配位环境对产物骨架结构、维度以及中心对称性的影响。对所报道的材料进行了全面的表征，包括元素分析、红外光谱、紫外-可见漫反射光谱、热分析以及偶极矩计算。晶体数据如下：Sc₂(SeO₃)₂(SeO₄)：单斜晶系，空间群P2₁/c（编号14），晶胞参数a = 6.5294(2) Å，b = 10.8557(4) Å，c = 12.6281(6) Å，β = 103.543(3)°，晶胞体积V = 870.21(6) ų，Z = 4；Sc₂(TeO₃)(SeO₃)(SeO₄)：单斜晶系，空间群P2₁/c（编号14），晶胞参数a = 6.5345(12) Å，b = 10.970(2) Å，c = 12.559(2) Å，β = 102.699(10)°，晶胞体积V = 878.3(6) ų，Z = 4；Sc₂(TeO₃)₃：单斜晶系，空间群P2₁/n（编号14），晶胞参数a = 5.2345(3) Å，b = 24.3958(15) Å，c = 6.8636(4) Å，β = 106.948(2)°，晶胞体积V = 838.42(9) ų，Z = 4。