Title: Selenium Oxide
CAS Registry Number: 7446-08-4
Additional Names: Selenium dioxide; selenious anhydride
Molecular Formula: O2Se
Molecular Weight: 110.96
Percent Composition: O 28.84%, Se 71.16%
Line Formula: SeO2
Literature References: Prepd by burning selenium in oxygen: Berzelius, Acad. Handl. Stockholm 39, 13 (1818); Ann. Chim. Phys. [2] 9, 160, 225, 337 (1818); by burning selenium in oxygen and nitrogen dioxide: Lenher, J. Am. Chem. Soc. 20, 559 (1898); by oxidizing selenium with nitric acid: A. P. Julien, ibid. 47, 1799 (1925). Toxicology: E. A. Cerwenka, W. C. Cooper, Arch. Environ. Health 3, 189 (1961). Review: Waitkins, Clark, Chem. Rev. 36, 235-289 (1945).
Properties: Lustrous, tetragonal needles. Acidic taste; leaves a burning sensation. Its yellowish green vapor has a pungent, sour smell. mp 340°; d1515 3.954. Vapor pressure (mm Hg): 12.5 at 70°; 20.2 at 94°; 39.0 at 181°; 760.0 at 315°; 848.0 at 320°. nD20 <1.76. Soly (parts/100 parts solvent) in water: 38.4 (14°); in methanol: 10.16 (11.8°); in 93% ethanol: 6.67 (14°); in acetone: 4.35 (15.3°); in acetic acid: 1.11 (13.9°). Sol in concd H2SO4. Stable to light and heat. Rapidly absorbs dry hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide to form the corresponding selenium oxyhalide. Reacts with ammonia to form nitrogen and selenium; in alcohol soln forms ammonium ethyl selenite, HN4(C2H5)SeO3. Yields nitrogen and black amorphous selenium with hydrazine; nitrogen and reddish-brown amorphous selenium with hydroxylamine hydrochloride. Forms selenic acid with nitric acid. Reduced by carbon and other organic substances.
Melting point: mp 340°
Index of refraction: nD20 <1.76
Density: d1515 3.954
CAUTION: Direct contact may cause intense local irritation of skin and eyes (Cerwenka, Cooper).
Use: In the manuf of other selenium compounds; as a reagent for alkaloids; as oxidizing agent: L. F. Fieser, M. Fieser, Reagents for Organic Chemistry vol. 1 (New York, Wiley, 1967) p 992. |