Synthesis and Structural Characterization of ... - Jacobs University

Chapter 1
Introduction
c) [(H 2 )W 12 O 40 ] 6−
d) [M 7 O 24 ] 6−
Figure 1.2 Polyhedral and ball-and-stick representations of some common isopolyanions. The
colour code is as follows: MO 6 octahedra (red), black spheres are metal centers and red ones
are oxygens.
1.2.2.2 Heteropolymetalates, [XxMmOy] q− :
a) The Keggin α-[XM 12 O 40 ] n− structure (T d symmetry) is composed of twelve MO 6 octahedra
arranged in four M 3 O 13 groups of three edge-shared MO 6 octahedra, linked via corner-sharing
to each other and to the central heteroatom XO 4 tetrahedron.
b) The Wells-Dawson structure (D 3h symmetry) is composed of two fused A-α-[XM 9 O 34 ] n−
via corners (M = Mo(VI), W(VI), X = P(V), As(V), and n = 6).
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