Title: Phosphorus Pentafluoride
CAS Registry Number: 7647-19-0
Molecular Formula: F5P
Molecular Weight: 125.97
Percent Composition: F 75.41%, P 24.59%
Line Formula: PF5
Literature References: Prepd by treating PF3 with bromine to form PF3Br which then disproportionates to PF5 and PBr5: Moissan, C.R. Hebd. Seances Acad. Sci. 100, 1348; 101, 1490 (1885); by heating P2O5 with CaF2: Lucas, Ewing, J. Am. Chem. Soc. 49, 1270 (1927); Booth, Bozarth, ibid. 55, 3890 (1933); from PCl5 and AsF3: Thorpe, Ann. 182, 201 (1876); Proc. Roy. Soc. 25, 122 (1877); O. Ruff, Die Chemie des Fluors (Berlin, 1920), p 29; Kwasnik in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 190-191; from PCl3 and CaF2: Muetterties et al., J. Inorg. Nucl. Chem. 16, 52 (1960); from phosphoryl fluoride, hydrogen fluoride and sulfur trioxide: Wiesboeck, US 3584999; US 3592594 (1971 to U.S. Steel). Reviews: Burg in Fluorine Chemistry vol. 1, J. H. Simons, Ed. (Academic Press, New York, 1950) pp 97-98; Kemmitt, Sharp, Adv. Fluorine Chem. 4, 197-198 (1965); Schmutzler, ibid. 5, 32-285 (1965).
Properties: Colorless gas. Fumes strongly in air. d (gas) 5.805 g/l. mp -93.8°. bp -84.6°. Trouton constant 21.8. Dipole moment: zero. High thermal stability. Does not attack dry glass even at 250°, but a slight trace of moisture leads to formation of POF3 and HF. Water hydrolysis ultimately yields phosphoric acid; intermediates are oxyfluophosphates. Lewis acid; forms complexes with amines, ethers, nitrates, sulfoxides, organic bases. Forms a cryst addn product PF5.NO2 at -10° which dissociates on warming. May be stored in steel cylinders.
Melting point: mp -93.8°
Boiling point: bp -84.6°
Density: d (gas) 5.805 g/l
CAUTION: Intensely irritating to skin, eyes, mucous membranes. Inhalation may cause pulmonary edema.
Use: Catalyst in ionic polymerization reactions. |