Chapter 4 - Jacobs University

Chapter 1
Introduction
shows no such chirality, 35,36,38 which has been suggested to be related to the greater rigidity of
the tungstate framework. 39 Possible reasons for the chirality and its effects on the numbers of
blue electrons the molybdo complex will accept have been discussed by Pope. 38 In 1979
Acerete 40,41 showed by 183 W NMR that the b geometrical isomer of [P 2 W 18 O 62 ] 6- differs from the
a isomer (Figure 1.5) by a 60° rotation of one W 3 O 13 cap.
Figure 1.3 Polyhedral representation of the α-[P 2 W 18 O 62 ] 6− Wells−Dawson anion. Two identical
fragments or hemispheres are easily identifiable, each composed of one capping triad and one
equatorial belt with six WO 6 octahedra.
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