6239. Molybdenum Trioxide

Nomenclature

CAS number: 1313-27-5
Molybdenum oxide (MoO3); molybdenum(VI) oxide; molybdic anhydride.
MoO3; mol wt 143.94.
Mo 66.65%, O 33.35%.

Description and references

Prepn from ammonium molybdate: Schumb, Hartford, J. Am. Chem. Soc. 56, 2613 (1934). Toxicity studies: L. T. Fairhall et al., “The Toxicity of Molybdenum,” U.S. Public Health Service Bulletin No. 293, Washington DC (1945) 36 pp.

Properties

White or slightly yellow to slightly bluish powder or granules. d426 4.696. mp 795°. Melts to dark-yellow liquid which solidifies to a yellowish-white cryst mass; sublimes at higher temp. bp 1155°. Sol in water (28°) 0.490 g/liter. Sol in concd mineral acids, in solns of alkali hydroxides, ammonia or potassium bitartrate; after strong ignition it is very slightly sol in acids.

Use

Chiefly as a reagent for chemical and trace metal analysis.