Chemistry:Aluminium molybdate

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Aluminium molybdate
Identifiers
3D model (JSmol)
ChemSpider
Properties
Al2(MoO4)3
Molar mass 533.77 g mol−1
Appearance grey, metallic solid/powder
odorless
Melting point 705 °C (1,301 °F; 978 K)
slightly soluble in water
Structure[1]
P21/a, No. 14
a = 15.3803(9) Å, b = 9.0443(1) Å, c = 17.888(1) Å
α = 90°, β = 125.382(3)°, γ = 90°
Hazards
NFPA 704 (fire diamond)
Flammability (red): no hazard codeHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity (yellow): no hazard codeSpecial hazards (white): no codeNFPA 704 four-colored diamond
1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is ☑Y☒N ?)
Infobox references

Aluminium molybdate is the chemical compound Al2(MoO4)3. It forms in certain hydrodesulfurization catalysts when alumina is doped with excess molybdenum.[2] When molybdates are used to inhibit corrosion in aluminum piping, the protective film formed is hydrated aluminum molybdate.[3][4] Although small quantities of aluminum molybdate form during aluminothermic reduction of molybdia, mechanical activation inhibits their formation.[5]

Large-scale samples can be prepared via sol-gel synthesis,[6] and have been proposed for molybdenum-99 storage in nuclear medicine.[7]

The room temperature crystal structure was refined using time-of-flight powder neutron diffraction data. It is monoclinic and isostructural with Fe2(MoO4)3 and Cr2(MoO4)3.[1] At high temperatures, the crystal rearranges to β‑Al2(MoO4)3, isostructural with scandium tungstate.[8]

Aluminum molybdate has a very low thermal expansion coefficient near room temperature.

References

  1. ↑ 1.0 1.1 Harrison, W. T. A.; Cheetham, A. K.; Faber, J. (1988). "The crystal structure of aluminium molybdate". Journal of Solid State Chemistry 76 (2): 328–333. doi:10.1016/0022-4596(88)90226-5. Bibcode: 1988JSSCh..76..328H. https://zenodo.org/record/1253956. 
  2. ↑ Medema, J.; van Stam, C.; de Beer, V. H. J.; Konings, A. J. A.; Koningsberger, D. C. (2 May 1977). "Raman spectroscopic study of Co–Mo/γ-Al2O3 catalysts". Journal of Catalysis 53: 386–400. 1978. doi:10.1016/0021-9517(78)90110-0. https://pure.tue.nl/ws/portalfiles/portal/1876217/620456.pdf. 
  3. ↑ McCune, R. C.; Shilts, R. L.; Ferguson, S. M. (1982-01-01). "A study of film formation on aluminum in aqueous solutions using Rutherford backscattering spectroscopy". Corrosion Science 22 (11): 1049–1065. doi:10.1016/0010-938X(82)90091-9. ISSN 0010-938X. https://dx.doi.org/10.1016/0010-938X%2882%2990091-9. 
  4. ↑ Byrne, Christian E.; Quesada Cangahuala, Nereida V.; D'Alessandro, Oriana; Deyá, Cecilia (2023-07-10). "Cerium and aluminum molybdates as inhibitors of the aluminum AA1050 corrosion process in aqueous NaCl solutions" (in en). Materials and Corrosion 75: 73–83. doi:10.1002/maco.202313940. ISSN 0947-5117. https://onlinelibrary.wiley.com/doi/10.1002/maco.202313940. 
  5. ↑ Sheybani, K.; Paydar, M. H.; Shariat, M. H. (2019-08-01). "Effect of mechanical activation on aluminothermic reduction of molybdenum trioxide". International Journal of Refractory Metals and Hard Materials 82: 245–254. doi:10.1016/j.ijrmhm.2019.04.015. ISSN 0263-4368. https://www.sciencedirect.com/science/article/pii/S0263436819301684. 
  6. ↑ Ari, Monica; Miller, Kimberly J.; Marinkovic, Bojan A.; Jardim, Paula M.; de Avillez, Roberto; Rizzo, Fernando; White, Mary Anne (19 October 2010). "Rapid synthesis of the low thermal expansion phase of Al2Mo3O12 via a sol–gel method using polyvinyl alcohol". Journal of Sol-Gel Science and Technology (Springer) 58: 121–125. 2011. doi:10.1007/s10971-010-2364-9. https://www.academia.edu/20446457. 
  7. ↑ Amin, M.; El-Amir, M. A.; Ramadan, H. E.; El-Said, H. (2018-11-01). "99Mo/99mTc generators based on aluminum molybdate gel matrix prepared by nano method" (in en). Journal of Radioanalytical and Nuclear Chemistry 318 (2): 915–922. doi:10.1007/s10967-018-6141-5. ISSN 1588-2780. https://doi.org/10.1007/s10967-018-6141-5. 
  8. ↑ Harrison, William T. A. (1995-11-01). "Crystal structures of paraelastic aluminum molybdate and ferric molybdate, β-Al2(MoO4)3 and β-Fe2(MoO4)3". Materials Research Bulletin 30 (11): 1325–1331. doi:10.1016/0025-5408(95)00157-3. ISSN 0025-5408. https://dx.doi.org/10.1016/0025-5408%2895%2900157-3. 

External links



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