Synthesis and Structural Characterization of ... - Jacobs University

Chapter 5
Published Results
polymolybdates. Hence, 26 combines three important features previously unknown for
tungstotellurate anions. First, the structure involves face-shared WO 6 octahedra; second, the
{W 10 } unit coordinated to tellurium(IV) atoms is novel; and third, the tellurium atoms adopt a
see-saw configuration.
Another novel tungstotellurate(IV), [NaTeW 15 O 54 ] 13−
(27), is present in a mixture of
products if the synthesis solution of 26 is heated. Single-crystal X-ray diffraction analysis
revealed that [NaTeW 15 O 54 ]·26H 2 O (Na-27) crystallizes in the orthorhombic space group
Pccn. Polyanion 27 is composed of a triangular assembly of 15 edge- and corner-shared WO 6
octahedra, surrounding a trigonal-pyramidal tellurium(IV) center located in the central cavity
and a capping sodium ion (Figure 5.5). The tellurium and the sodium atom, both closely
associated with the polyanion, are disoredered showing 50 % occupancy for each. Polyanion
27 is composed of three identical {W 5 } building-blocks which are made up of five WO 6
octahedra.
Figure 5.5. Ball-and-stick representations of [NaTeW 15 O 54 ] 13− (27). The color code is as the
same as Figure 5.2.
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