Phosphorus trifluoride 1830788 221165776 2008-06-23T09:29:47Z DOI bot 6652755 Citation maintenance. You can [[WP:DOI|use this bot]] yourself! Please [[User:DOI_bot/bugs|report any bugs]]. {{Chembox new | Name = Phosphorus trifluoride | ImageFile = Phosphorus-trifluoride-2D-dimensions.png <!-- | ImageSize = 150px --> | ImageName = Phosphorus trifluoride | ImageFile1 = Phosphorus-trifluoride-3D-vdW.png <!-- | ImageSize1 = 150px --> | ImageName1 = Phosphorus trifluoride | IUPACName = Phosphorus trifluoride<br />Phosphorus(III) fluoride<br />Trifluorophosphane<br />Trifluorophosphorus | OtherNames = Trifluorophosphine | Section1 = {{Chembox Identifiers | CASNo = 7783-55-3 }} | Section2 = {{Chembox Properties | Formula = PF<sub>3</sub> | MolarMass = 87.98 g/mol | Appearance = colorless gas | Density = 3.91 g/l, gas | Solubility = <br />slow hydrolysis | MeltingPt = &minus;151.5 °C (121.7 K) | BoilingPt = &minus;101.8 °C (171.4 K) | pKb = }} | Section3 = {{Chembox Structure | MolShape = pyramidal | Dipole = 1.03 [[Debye|D]] }} | Section7 = {{Chembox Hazards | ExternalMSDS = | EUClass = not listed | FlashPt = non-flammable }} | Section8 = {{Chembox Related | OtherAnions = [[Phosphorus trichloride]]<br />[[Phosphorus tribromide]]<br />[[Phosphorus triiodide]] | OtherCations = [[Nitrogen trifluoride]]<br />[[Arsenic trifluoride]] | Function = [[ligand]]s | OtherFunctn = [[Carbon monoxide]] | OtherCpds = [[Phosphorus pentafluoride]] }} }} '''Phosphorus trifluoride''' (formula [[Phosphorus|P]][[Fluorine|F]]<sub>3</sub>, is a colourless and odourless [[gas]]. It is highly toxic and it reacts slowly with water. Its main use is as a [[ligand]] in [[Complex (chemistry)|metal complexes]]. As a ligand it parallels [[carbon monoxide]]<ref name="ref6">J. Chatt, ''Nature'' '''165''', 637-8 (1950).</ref> in [[metal carbonyl]]s, and indeed its toxicity is due to the fact that it binds with the [[iron]] in blood [[hemoglobin|haemoglobin]] in a similar way to carbon monoxide. ==Physical properties== Phosphorus trifluoride has a bond angle of 96.3°. [[Gas]]eous PF<sub>3</sub> has a [[standard enthalpy change of formation|standard enthalpy of formation]] of -945 kJ/mol (-226 [[Calorie|kcal]]/ [[mole (unit)|mol]]). The phosphorus atom has an [[Nuclear magnetic resonance|NMR]] chemical shift of 97 ppm (downfield of [[phosphoric acid|H<sub>3</sub>PO<sub>4</sub>]]). ==Properties== Phosphorus trifluoride [[Hydrolysis reaction|hydrolyses]] especially at [[Alkali|high pH]], but it is less hydrolytically sensitive than [[phosphorus trichloride]]. It does not attack glass except at high temperatures, and anhydrous [[potassium hydroxide]] may be used to dry it with little loss. With hot [[metal]]s, phosphides and fluorides are formed. With [[Lewis base]]s such as [[ammonia]] addition products (adducts) are formed, and PF<sub>3</sub> is oxidised by [[Redox|oxidising agent]]s such as [[bromine]] or [[potassium permanganate]]. As a ligand for transition metals, PF<sub>3</sub> is a strong π-acceptor.<ref name="ref1 p494">N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997, p 494</ref> It forms a variety of [[Complex (chemistry)|metal complexes]] with [[metal]]s in low [[oxidation state]]s. PF<sub>3</sub> forms several complexes for which the corresponding CO derivatives (see [[metal carbonyl]]) are unstable or nonexistent. Thus, Pd(PF<sub>3</sub>)<sub>4</sub> is known, but Pd(CO)<sub>4</sub> is not.<ref name="ref9">D. Nicholls, ''Complexes and First-Row Transition Elements'', Macmillan Press, London, 1973.</ref><ref name="ref10">Kruck, T.“Trifluorphosphin-Komplexe von Übergangsmetallen” Angewandte Chemie 1967, volume 79, p 27-43. DOI: 10.1002/ange.19670790104</ref><ref> Clark, R. J.; Busch, M. A. “Stereochemical studies of metal carbonylphosphorus trifluoride complexes” Accounts of Chemical Research, 1973, volume 6, pages 246-52.DOI: 10.1021/ar50067a005.</ref> Such complexes are usually prepared directly from the related [[metal carbonyl]] compound, with loss of [[Carbon monoxide|CO]]. However, [[Nickel]] [[metal]] reacts directly with PF<sub>3</sub> at 100 °C under 35 [[Pascal (unit)|MPa]] pressure to form Ni(PF<sub>3</sub>)<sub>4</sub>, which is analogous to [[Nickel carbonyl|Ni(CO)<sub>4</sub>]]. Cr(PF<sub>3</sub>)<sub>6</sub>, the analogue of [[Chromium hexacarbonyl|Cr(CO)<sub>6</sub>]], may be prepared from [[dibenzenechromium]]: :[[Dibenzenechromium|Cr(C<sub>6</sub>H<sub>6</sub>)<sub>2</sub>]] + 6PF<sub>3</sub> → Cr(PF<sub>3</sub>)<sub>6</sub> + 2[[Benzene|C<sub>6</sub>H<sub>6</sub>]] ==Preparation== Phosphorus trifluoride is usually prepared from [[phosphorus trichloride]] via halogen exchange using various [[fluoride]]s, e.g. [[hydrogen fluoride]], [[calcium fluoride]], [[arsenic trifluoride]], [[antimony trifluoride]], or [[zinc fluoride]]:<ref>A. A. Williams, in ''Inorganic Syntheses'', Vol. V, 95-7 (1946).</ref><ref>''Nouveau traité de chimie minérale : Tome X'', Masson, Paris, France, 1956.</ref><ref>{{cite journal | author = Ronald J. Clark, Helen Belefant, Stanley M. Williamson | title = Phosphorus Trifluoride | journal = [[Inorganic Syntheses]] | volume = 28 | pages = 310–315 | doi = 10.1002/9780470132593.ch77 | year = 1990}}</ref> :2[[Phosphorus trichloride|PCl<sub>3</sub>]] + 3[[Zinc fluoride|ZnF<sub>2</sub>]] → 2PF<sub>3</sub> + 3[[Zinc chloride|ZnCl<sub>2</sub>]] ==Biological activity== Phosphorus trifluoride is similar to [[carbon monoxide]] in that it is a gas which strongly binds to [[iron]] in [[haemoglobin]], preventing the blood from absorbing oxygen. ==Precautions== PF<sub>3</sub> is highly [[poison|toxic]], comparable to [[phosgene]].<ref>Greenwood, 1997</ref> ==External links== *[http://www.npi.gov.au/database/substance-info/profiles/44.html National Pollutant Inventory - Flouride and compounds fact sheet] ==References== {{Citationstyle|date=September 2007}} <references/> * ''Handbook of Chemistry and Physics'', 71st edition, CRC Press, Ann Arbor, Michigan, 1990. * J. March, ''Advanced Organic Chemistry'', 4th ed., p. 723, Wiley, New York, 1992. * ''The Merck Index'', 7th edition, Merck & Co, Rahway, New Jersey, USA, 1960. * A. D. F. Toy, ''The Chemistry of Phosphorus'', Pergamon Press, Oxford, UK, 1973. [[Category:Phosphorus compounds]] [[Category:Fluorides]] [[Category:Nonmetal halides]] [[de:Phosphor(III)-fluorid]]