Title: Sulfur Hexafluoride
CAS Registry Number: 2551-62-4
Molecular Formula: F6S
Molecular Weight: 146.06
Percent Composition: F 78.04%, S 21.95%
Line Formula: SF6
Literature References: Prepd by direct fluorination of sulfur or sulfur dioxide: Moissan, Lebeau, Compt. Rend. 130, 865, 984 (1900); eidem, Ann. Chim. Phys. [7] 26, 147 (1902); Schumb, Inorg. Synth. 3, 119 (1950); Kwasnik in Handbook of Preparative Inorganic Chemistry Vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 169-170. Reviews: Cady, "Fluorine-Containing Compounds of Sulfur" in Adv. Inorg. Chem. Radiochem. 2, 105-157 (1960); Kemmitt, Sharp, Adv. Fluorine Chem. 4, 218-219 (1965).
Properties: Colorless, odorless gas. One of the heaviest known gases; density approx 5 times that of air. mp -50.8°. Sublimes at -63.8°. Crit temp 45.6°. d (liq; -50.8°) 1.88. Sparingly sol in water, somewhat more in alcohol. At 25° and 1 atm 0.297 ml SF6 dissolves in 1.0 ml of transformer oil. Thermodynamically unstable but kinetically stable gas. This stability explained by symmetrical, octahedral structure of the molecule. Inert to nucleophilic attack. Does not attack glass. No fluorine exchange with HF. Stable to silent electrical discharge. Unchanged at 500°.
Melting point: mp -50.8°
Density: d (liq; -50.8°) 1.88
CAUTION: Potential symptoms of overexposure are asphyxia; increased breathing rate and pulse rate; slight muscle incoordination, emotional upset; fatigue, nausea, vomiting, convulsions. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 288.
Use: In electrical circuit interrupters. In electronic ultra-high frequency piping. |