Lanthanoidtellurate Ln₂TeO₆

Abstract

Die Kristallstruktur von La2TeO6, orthorhombisch, a = 551,0, b = 944,1 und c = 1038,7 pm, und kristallographische Daten der mit gleicher Struktur kristallisierenden, bisher als hexagonal beschriebenen Lanthanoidtellurate (bis Yb2TeO6 einschließlich) wurden ermittelt. Die Na2SiF6‐Struktur für eine zweite Form der Ytterbiumverbindung wird bestätigt.

The family of Ln2TeO6 compounds (Ln=Y, La, Sm and Gd): Characterization and synthesis by the Pechini sol–gel process

“…1. The XRD results indicate that all samples crystallized isostructurally with the orthorhombic La 2 TeO 6 -type structure in the space group P2 1 2 1 2 1 [7].…”

“…A description of the crystal structure of Ln 2 TeO 6 (Ln = Y, La, Sm, Gd) can be found in literature [7][8][9] and it is briefly recalled here. The rare-earth cations occupy two independent atomic positions and are coordinated sevenfold by oxygen in form of a square-triangle polyhedron and capped trigonal prism, respectively.…”

“…In 1987, Trömel et al have reported the crystal structure, from single crystal data, of La 2 TeO 6 and Yb 2 TeO 6 and proved that both phases crystallize in the orthorhombic system with space group P2 1 2 1 2 1 (no. 19) [7]. In the last years Schleid and co-workers have described the synthesis and the crystal structure of Gd 2 TeO 6 and Y 2 TeO 6 .…”

Electronic, structural, and optical properties of host materials for inorganic phosphors

“…La 2 TeO 6 has an orthorhombic crystal structure, space group P2 1 2 1 2 1 (No. 19), with 36 atoms in the unit cell, all of them in 4a Wyckoff positions [39]. Lanthanum atoms in this structure are found occupying two different sites.…”

Red-emitting Ln2−xEuxTe2O6:RE (Ln=La, Y; RE=Sm3+, Gd3+) phosphors prepared by the Pechini sol–gel method

“…Ln 2 TeO 6 crystallize in the orthorhombic system with space group P2 1 2 1 2 1 , where the cations occupy two independent atomic positions and are coordinated sevenfold by oxygen in form of a square-triangle polyhedron and a capped trigonal prism, respectively. Both coordination polyhedra are characterized by the lack of inversion symmetry [14]. It is known that for Eu 3+ cations located at a non-centrosymmetric site, the preferred transition is 5 D 0 → 7 F 2 and the emission is red.…”