Vanadium-Substituted Keggin Ion
Figure 1 - Molecular structure of
H5V2Mo10O40 from crystallography.
Phosphorus atom is white, oxygen atoms are red,
molybdenum atoms are blue, vanadium atoms are yellow. Hydrogen atoms have been
omitted for clarity.
This is an example of the "Keggin" structure. Replacement of the molybdenum
atoms with tungsten is possible, which modifies the selectivity.
Catalysts are important, because they speed up chemical reactions, making many
more reactions commercially feasible. These Keggin catalysts are particularly
interesting, because they can act as acid catalysts (donating H+), or oxidation
catalysts (accepting electrons). The subtle interplay between these two modalities
yields the final product.
Figure 2 - Molecular structure of
H5Mo12O40 from crystallography.
Phosphorus atom is purple, oxygen atoms are red,
molybdenum atoms are yellow. Hydrogen atoms have been
omitted for clarity.
Figure 3 - Molecular structure of
H5Mo12O40 from crystallography.
Phosphorus atom is purple, oxygen atoms are red,
molybdenum atoms are yellow. Hydrogen atoms have been
omitted for clarity.
Figure 3 - Molecular structure of "Dawson" ion from crystallography.
Dawson is essentially a dimer of the Keggin ion, with increased solubility in aqeuous solution.
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