Phosphorus trifluoride

Names
IUPAC names Phosphorus trifluoride Phosphorus(III) fluoride Trifluorophosphane Trifluoridophosphorus Perfluorophosphane
Other names Trifluorophosphine Phosphorous fluoride TL-75
Identifiers
CAS Number	7783-55-3 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30205 Y
ChemSpider	56416 Y
ECHA InfoCard	100.029.098
PubChemCID	62665
RTECS number	TH3850000
UNII	496073DYBF Y
CompTox Dashboard(EPA)	DTXSID6064826
InChI InChI=1S/F3P/c1-4(2)3 Y Key: WKFBZNUBXWCCHG-UHFFFAOYSA-N Y InChI=1/F3P/c1-4(2)3 Key: WKFBZNUBXWCCHG-UHFFFAOYAK
SMILES FP(F)F
Properties
Chemical formula	PF3
Molar mass	87.968971 g/mol
Appearance	colorless gas
Density	3.91 g/L, gas
Melting point	−151.5 °C (−240.7 °F; 121.6 K)
Boiling point	−101.8 °C (−151.2 °F; 171.3 K)
Critical point (T,P)	−2.05 °C (28.3 °F; 271.1 K); 42.73 standard atmospheres (4,329.6 kPa; 628.0 psi)
Solubility in water	slow hydrolysis
Structure
Molecular shape	Trigonal pyramidal
Dipole moment	1.03D
Hazards
NFPA 704 (fire diamond)	3 0 1
Flash point	Non-flammable
Related compounds
Otheranions	Phosphorus trichloride Phosphorus tribromide Phosphorus triiodide Phosphane
Othercations	Nitrogen trifluoride Arsenic trifluoride Antimony trifluoride Bismuth trifluoride
Relatedligands	Carbon monoxide
Related compounds	Phosphorus pentafluoride
Supplementary data page
Phosphorus trifluoride (data page)
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Phosphorus trifluoride (formulaPF₃), is a colorless and odorlessgas. It is highly toxic and reacts slowly with water. Its main use is as aligand inmetal complexes. As a ligand, it parallelscarbon monoxide inmetal carbonyls,^[1] and indeed its toxicity is due to its binding with theiron in bloodhemoglobin in a similar way to carbon monoxide.

Phosphorus trifluoride has an F−P−F bond angle of approximately 96.3°.Gaseous PF₃ has astandard enthalpy of formation of −945 kJ/mol (−226 kcal/mol). The phosphorus atom has anuclear magnetic resonance chemical shift of 97 ppm (downfield ofH₃PO₄).

Phosphorus trifluoridehydrolyzes especially athigh pH, but it is less hydrolytically sensitive thanphosphorus trichloride. It does not attack glass except at high temperatures, and anhydrouspotassium hydroxide may be used to dry it with little loss. With hotmetals, phosphides and fluorides are formed. WithLewis bases such asammonia addition products (adducts) are formed, and PF₃ is oxidized byoxidizing agents such asbromine orpotassium permanganate.

As a ligand for transition metals, PF₃ is a strong π-acceptor.^[2]It forms a variety ofmetal complexes withmetals in lowoxidation states. PF₃ forms several complexes for which the corresponding CO derivatives (seemetal carbonyl) are unstable or nonexistent. Thus, Pd(PF₃)₄ is known, but Pd(CO)₄ is not.^[3][4][5] Such complexes are usually prepared directly from the relatedmetal carbonyl compound, with loss ofCO. However,nickelmetal reacts directly with PF₃ at 100 °C under 35MPa pressure to form Ni(PF₃)₄, which is analogous toNi(CO)₄. Cr(PF₃)₆, the analogue ofCr(CO)₆, may be prepared fromdibenzenechromium:

Cr(C₆H₆)₂ + 6 PF₃ → Cr(PF₃)₆ + 2C₆H₆

Ball-and-stick model of [Pt(PF3)4]	Space-filling model of [Pt(PF3)4]

Phosphorus trifluoride is usually prepared fromphosphorus trichloride via halogen exchange using variousfluorides such ashydrogen fluoride,calcium fluoride,arsenic trifluoride,antimony trifluoride, orzinc fluoride:^[6][7][8]

2PCl₃ + 3ZnF₂ → 2 PF₃ + 3ZnCl₂

Phosphorus trifluoride is similar tocarbon monoxide in that it is a gas which strongly binds toiron inhemoglobin, preventing the blood from absorbing oxygen.

PF₃ is highlytoxic, comparable tophosgene.^[9]

• Toy, A. D. F. (1973).The Chemistry of Phosphorus. Oxford, UK: Pergamon Press.
• Greenwood, Norman N.; Earnshaw, Alan (1997).Chemistry of the Elements (2nd ed.).Butterworth-Heinemann.doi:10.1016/C2009-0-30414-6.ISBN 978-0-08-037941-8.
• Lide, D. R., ed. (1990).Handbook of Chemistry and Physics (71st ed.). Ann Arbor, MI: CRC Press.ISBN 978-0-8493-0471-2.
• March, J. (1992).Advanced Organic Chemistry (4th ed.). New York: Wiley. p. 723.ISBN 978-0-471-60180-7.
• Stecher, P. G., ed. (1960).The Merck Index (7th ed.). Rahway, NJ, USA: Merck & Co.
• Holmes, R. R. (1960). "An Examination of the Basic Nature of the Trihalides of Phosphorus, Arsenic and Antimony".Journal of Inorganic and Nuclear Chemistry.12 (3–4):266–275.doi:10.1016/0022-1902(60)80372-7.

• National Pollutant Inventory - Fluoride and compounds fact sheet
• WebBook page for PF3

• Phosphorus fluorides
• Phosphorus(III) compounds
• Blood agents

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