Synthesis and Structural Characterization of ... - Jacobs University

Chapter 5
Unpublished Results
Each {Te 12 Mo 22 } unit can be considered as an assembly of three types of ‘building blocks’
(see Figure 5.11 and 5.12) and this unit can be considered as two caps and a belt. Each cap (a
hexamolybdate {Mo 6 } subunit) consists of three building blocks:
- One trimolybdate {Mo 3 } fragment (green in Figure 5.12) made of three edge-shared
[MoO 6 ] octahedra connected via a μ 3 -oxo bridge. This fragment can be viewed as a
single ‘triad’ of the well-known Keggin and Wells-Dawson structures. 1a
- One dimolybdate {Mo 2 } subunit (red in Figure 5.12) made of two edge-shared
[MoO 6 ] octahedra connected through two μ 2 -oxo bridges.
- One monomolybdate {Mo 1 } subunit (blue in Figure 5.12). These three subunits
({Mo 3 }, {Mo 2 }, and {Mo 1 }) are connected to each other via three corners forming a
hexamolybdate {Mo 6 } subunit. The {Mo 3 } subunit shares two corners with the
adjacent {Mo 2 } and a corner with the {Mo 1 } subunit to build up this {Mo 6 } subunit.
Belt ({Mo 10 } subunit) consists of two building blocks:
- Two tetramolybdates {Mo 4 } subunits (red in Figure 5.12) made of four edge-shared
[MoO 6 ] octahedra connected through six μ 2 -oxo bridges.
- Two monomolybdate {Mo 1 } subunits (blue in Figure 5.12). These two types of the
subunits ({Mo 4 } and {Mo 1 }) are connected to each other via corners forming a
decamolybdate {Mo 10 } subunit.
The two caps {Mo 6 } and the belt {Mo 10 } units are connected to each other via Te−O−Mo μ 2 -
oxo bridges, through six Te 4+ ions each. The Te atoms have coordination number three and
four leading to a trigonal-pyramidal and a see-saw coordination geometry.
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