7359. Phosphorus Trifluoride

Nomenclature

CAS number: 7783-55-3
F3P; mol wt 87.97.
F 64.79%, P 35.21%.
PF3.

Description and references

Prepd by halogen exchange between PCl3 and AsF3: Moissan, Compt. Rend. 100, 272 (1885); Hoffman, Inorg. Synth. 4, 149 (1953); between PCl3 and ZnF2: Williams, ibid. 5, 95 (1957); between PCl3 and CaF2 or SbF3: Booth, Bozarth, J. Am. Chem. Soc. 61, 2927 (1939); Muetterties et al., J. Inorg. Nucl. Chem. 16, 52 (1960); between PCl3 and HF: Kwasnik in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 189-190. Reviews: Burg in Fluorine Chemistry vol. 1, J. H. Simons, Ed. (Academic Press, New York, 1950) pp 98-100; Kemmitt, Sharp, Adv. Fluorine Chem. 4, 198-199 (1965); Schmutzler, ibid. 5, 32-285 (1965).

Properties

Colorless gas. Does not fume in air. Does not attack glass except at high temps. Poisonous. d (gas) 3.907 g/l. mp -151.30°. bp -101.38°. Critical temp -2.05°; critical press. 42.69 atm. May be stored in steel cylinders or in glass, also in a gasometer over Hg. Slowly hydrolyzed by water. Absorbed by aq bases at a rate increasing with pH, producing a fluophosphite which boiling aq HNO3 does not convert to phosphate. Anhydr KOH may be used to dry PF3 with little loss. Dry NH3 forms a solid addn product. Aq oxidizers such as chromic acid, permanganate, or bromine rapidly destroy PF3, and alcohols convert it to alkyl phosphite. Phosphides and fluorides are formed upon reaction with hot metals.

Caution

See Phosphorus Pentafluoride.