Molybdate
A molybdate is a chemical compound containing anions made of molybdenum and oxygen, with molebdenum in the +6 oxidation state. The simple molybdate ion, MoO2−4, has the same shape as sulfate, chromate, and orthotungstate: a central atom with four oxygen atoms around it. Like the tungstates, bigger anions are polyoxometallates where each molybdenum atom has six oxygen atoms around it.
Uses
[change | change source]Unlike tungstate, molybdate is not the main ore of molybdenum, which is mined as the mineral molybdenite (molybdenum disulfide). Some molybdate ores exist, like wulfenite and powellite.[1] Ammonium molybdate is made as part of the refining of molybdenum ore.[2]
Polymolybdate derivatives have been used in analytical chemistry to test for reducing agents since the late 18th century, when Carl Wilhelm Scheele discovered ammonium phosphomolybdate, the first salt of a heteropoly acid.[3]
Molybdate can be used as a less toxic alternative to chromate to stop corrosion of some metals like aluminium alloys and some steels.[4]
In biology
[change | change source]Orthomolybdate is the main source of molybdenum for living things. Molybdate is added to the ligand molybdopterin to make molybdenum cofactor, which many enzymes need to work properly.[5] Orthomolybdate is also needed to make FeMoco, used by the most common type of nitrogenase.[6]
References
[change | change source]- ↑ Hindawi, Atef S.; Tahawy, Rafat; Abdelbasir, Sabah. M.; El-Gendy, Ahmed A.; Ibrahim, Hosny (2025). "Management and valuation of spent molybdenum catalyst: A review". Separation and Purification Technology. 376 134018. doi:10.1016/j.seppur.2025.134018.
- ↑ "Molybdenum Processing". International Molybdenum Association. Retrieved 2026-04-06.
- ↑ Müller, Achim; Meyer, Jochen; Krickemeyer, Erich; Diemann, Ekkehard (1996). "Molybdenum Blue: A 200 Year Old Mystery Unveiled". Angewandte Chemie International Edition in English. 35 (11): 1206–1208. doi:10.1002/anie.199612061.
- ↑ Milošev, Ingrid (2024). "Corrosion inhibition of aluminium alloys by molybdate ions: A critical review of the chemistry, mechanisms and applications". Corrosion Science. 229 111854. Bibcode:2024Corro.22911854M. doi:10.1016/j.corsci.2024.111854.
- ↑ Probst, Corinna; Yang, Jing; Krausze, Joern; Hercher, Thomas W.; Richers, Casseday P.; Spatzal, Thomas; Kc, Khadanand; Giles, Logan J.; Rees, Douglas C.; Mendel, Ralf R.; Kirk, Martin L.; Kruse, Tobias (2021). "Mechanism of molybdate insertion into pterin-based molybdenum cofactors". Nature Chemistry. 13 (8): 758–765. Bibcode:2021NatCh..13..758P. doi:10.1038/s41557-021-00714-1. PMC 8325642. PMID 34183818.
- ↑ Hernandez, Jose A.; George, Simon J.; Rubio, Luis M. (2009). "Molybdenum Trafficking for Nitrogen Fixation". Biochemistry. 48 (41): 9711–9721. Bibcode:2009Bioc...48.9711H. doi:10.1021/bi901217p. PMC 2999624. PMID 19772354.