Available online 25 January 2008.
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Colorless, polyhedral single crystals of Na3Ga3Te2O12 have been synthesized for the first time by supercritical hydrothermal techniques using NaOH, Ga2O3, TlNO3 and TeO2 as reagents. Na3Ga3Te2O12 was characterized by single-crystal and powder X-ray diffractions, IR, Raman, UV–vis diffuse reflectance spectroscopies and thermogravimetric analysis. Na3Te2Ga3O12 crystallizes in the cubic space group Ia-3d (No. 230) with a = 12.3604(14) Å, V = 1888.4(4) Å3, and Z = 8. Na3Ga3Te2O12 exhibits a garnet structure-type with the Te6+ and Ga3+ cations occupying the octahedral and tetrahedral sites, respectively.
Keywords: Supercritical hydrothermal synthesis; Tellurium; Garnet; Three-dimensional structure
Fig. 1. Ball-and-stick diagrams showing (a) the Te–O–Ga–O building unit (16-membered ring) viewed on the ab-plane and (b) one layer of Na3Ga3Te2O12 viewed on the bc-plane.
Fig. 2. Polyhedral (Te6+/Ga3+) representation of Na3Ga3Te2O12 viewed down the [11−1] direction. The Na+ atoms have been omitted for clarity.
Fig. 3. Scanning electron micrographs of some Na3Ga3Te2O12 crystals.
Crystal data for Na3Ga3Te2O12
) = ∑||Fo
| − |Fc
) = [∑w
Atomic coordinates for Na3Ga3Te2O12
is defined as one third of the trace of the orthogonalized Uij
Bond distances (Å) and angles (°) for Na3Ga3Te2O12
Comparison of lattice constants (a, Å) among similar A3B3M2O12 garnets (M = Te6+, W6+)
Data from (presumably) powder X-ray diffraction; no standard deviation provided.
Infrared and Raman vibrations for Na3Ga3Te2O12