A new oxyfluorotellurate(IV), InTe2O5F.

A new oxyfluorotellurate(IV), indium fluoridopentaoxidotellurate(IV), InTe2O5F, has been synthesized by solid-state reaction and structurally characterized. The crystal structure consists of a three-dimensional framework formed by InO4F2 octahedra and Te2O5 units. The InO4F2 octahedra are linked through the F atoms, which lie on twofold axes, giving rise to helical chains.

GeTe(2)O(6), a germanium tellurate(IV) with an open framework.

The structure of an already evidenced but still uncharacterized GeTe(2)O(6) phase consists of isolated GeO(6) octahedra connected via isolated TeO(3) units. The germanium cations occupy a site with 1 symmetry. The Te and O atoms are in general positions of the P2(1)/n space group.

New vanadium(IV) and titanium(IV) oxyfluorotellurates(IV): V2Te2O7F2 and TiTeO3F2.

As part of a continuing study of oxyfluorotellurates(IV), materials likely to present interesting nonlinear optical properties, two new phases, titanium(IV) tellurium(IV) trioxide difluoride, TiTeO(3)F(2), and divanadium(IV) ditellurium(IV) heptaoxide difluoride, V(2)Te(2)O(7)F(2), have been characterized and present, respectively, titanium and vanadium in the tetravalent state. The TiTeO(3)F(2) structure is based on linear double rows of TiO(3)F(3) polyhedra sharing vertices. These rows are connected to adjacent rows via two vertices of Te(2)O(5) bipolyhedra.

Two new types of oxyfluorotellurates(IV): ScTeO3F and InTeO3F.

In the course of a general study of oxyfluorotellurates(IV), materials likely to exhibit interesting nonlinear optical properties, the crystal structures of the new phases scandium tellurium trioxide fluoride, ScTeO(3)F, and indium tellurium trioxide fluoride, InTeO(3)F, belonging to two different structural types and also differing from that of the recently published MTeO(3)F (M = Fe, Ga and Cr) series, have been determined. The ScTeO(3)F structure can be described as an intergrowth of two different layers of scandium octahedra connected via isolated TeO(3) groups. The scandium ions occupy two different sites with .

Sodium iodine(V) oxyfluoride, NaIO2F2.

As an extension of a general structural study concerning fluorides and oxyfluorides of cations presenting a stereochemically active electronic lone pair, until now limited to tellurium(IV) phases, the previously unknown structure of NaIO(2)F(2) corresponds to a new structure type based on isolated IO(2)F(2)(-) polyhedra forming sheets separated by Na(+) layers. The sodium ion is octahedrally coordinated with 2/m site symmetry, while the I(V) atom has m2m symmetry with a stereochemically active lone electron pair. The O and F atoms (both with m symmetry) are bonded to the I(V) atoms in a fully ordered manner.

New oxyfluorotellurates(IV): MTeO3F (M = FeIII, GaIII and CrIII).

The crystal structures of the new isomorphous compounds iron(III) oxyfluorotellurate(IV), FeTeO(3)F, gallium(III) oxyfluorotellurate(IV), GaTeO(3)F, and chromium(III) oxyfluorotellurate(IV), CrTeO(3)F, consist of zigzag chains of MO(4)F(2) distorted octahedra alternately sharing O-O and F-F edges and connected via TeO(3) trigonal pyramids. A full O/F anionic ordering is observed and the electronic lone pair of the Te(IV) cation is stereochemically active.