Molybdate

In chemistry, a molybdate is a compound containing an oxyanion with molybdenum in its highest oxidation state of +6: O−−Mo(=O)2−O−.

The larger oxyanions are members of group of compounds termed polyoxometalates, and because they contain only one type of metal atom are often called isopolymetalates.

[1] In the larger anions molybdenum is generally, but not exclusively, 6 coordinate with edges or vertices of the MoO6 octahedra being shared.

The octahedra are distorted, typical M-O bond lengths are: The Mo8O4−26 anion contains both octahedral and tetrahedral molybdenum and can be isolated in 2 isomeric forms, alpha and beta.

The space filling model of the heptamolybdate image shows the close packed nature of the oxygen atoms in the structure.

[9] When MoO3, molybdenum trioxide is dissolved in alkali solution the simple MoO2−4 anion is produced: As the pH is lowered, condensations ensue, with loss of water and the formation of Mo–O–Mo linkages.

In terms of scale, the largest consumer of molybdate is as a precursor to catalysts for hydrodesulfurization, the process by which sulfur is removed from petroleum.

[17] Radioactive molybdenum-99 in the form of molybdate is used as the parent isotope in technetium-99m generators for nuclear medicine imaging.

[21] Additionally, it is used in the colorimetric analysis of phosphate concentration in association with the dye malachite green.