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

Abstract

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 Se(4+) and Te(4+) 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) Å(3), 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) Å(3), 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) Å(3), and Z = 4.

Incorporation of Sulfate or Selenate Groups into Oxotellurates(IV): I. Calcium, Cadmium, and Strontium Compounds

“…So far, only a few metal oxotellurate(IV) phases with additional X O 4 groups have been reported, mostly prepared under hydrothermal conditions. This includes the sulfates Al 2 (OH) 2 (SO 4 )(TeO 3 ), Fe 2 (TeO 3 ) 2 (SO 4 )(H 2 O) 3 , Cu 7 (OH) 6 (TeO 3 ) 2 (SO 4 ) 2 , Cu 7 TeO 4 (SO 4 ) 5 KCl, the series RE 2 M (TeO 3 ) 2 (SO 4 ) 2 ( RE = rare earth metal; M = Cu, Co, Zn),, Pu(TeO 3 )(SO 4 ), Th(TeO 3 )(SO 4 ), Ce 2 (Te 2 O 5 )(SO 4 ) 2 , M 2 (TeO 3 )(SO 4 )H 2 O ( M = Co, Mn), and BiCu 2 (TeO 3 )(SO 4 )‐(OH) 3 , and to a much lesser extend the selenates Sc 2 (TeO 3 )‐(SeO 3 )(SeO 4 ) (also comprising an oxoselenate(IV) group), Bi 2 (TeO 3 ) 2 (SeO 4 ) and the already noted mercury compounds Hg 3 (SeO 4 )(TeO 3 ) 2 and Hg 3 (SeO 4 )(Te 4 O 10 ) …”

YCu(TeO3)2(NO3)(H2O)3: a novel layered tellurite

“…Tellurium is stable in numerous oxidation states and shows large diversity in bonding . Its +IV and +VI oxidation states are of greatest interest in relation to naturally occurring weathering products of minerals, and are able to form a wide variety of oxide polyhedra, with TeO 3 2À most prevalent (Song et al, 2014). The TeO 3 2À anion shows a wide variety of connectivities, with three oxido ligands and the 5s 2 electron lone pair occupying the vertices of the distorted polyhedra, and are found in a variety of layer and chain structures in inorganic compounds (Johansson & Lindqvist, 1978).…”

Zn(H2C3N3O3)2·3H2O: the first single-d10transition metal based ultraviolet hydroisocyanurate crystal with large birefringence

“…For instance, ambientpressure phase TeZnO 3 (with ZnO 5 polyhedron) and highpressure phase TeZnO 3 (with ZnO 4 and ZnO 6 polyhedra) show a variety of coordination environments for Zn atoms, and high-pressure phase TeZnO 3 also exhibits a larger band gap (E g = 6 eV) 22 compared to other transition metal tellurites such as Sc 2 (TeO 3 ) 3 (E g = 3.7 eV). 23 Similarly in K 2 Zn(H 2 C 3 N 3 O 3 ) 4 •4H 2 O (E g = 5.23 eV, with the ZnO 6 polyhedron), 24 upon introducing Zn atoms into K 2 (HC 3 N 3 O 3 ) (E g = 4.94 eV), 25 the band gap increased. Therefore, Zn-based cyanurates are a promising system to explore optional functional crystals with wide ultraviolet transparency.…”