Thiophosphoryl fluoride is aninorganic molecular gas with formulaPSF3 containingphosphorus,sulfur andfluorine. It spontaneously ignites in air and burns with acool flame. The discoverers were able to have flames around their hands without discomfort,[5] and called it "probably one of the coldest flames known".[5] The gas was discovered in 1888.[5]
It is useless for chemical warfare as it burns immediately and is not toxic enough.[6]
Thiophosphoryl fluoride was discovered and named by J. W. Rodger andT. E. Thorpe in 1888.[5][7]
They prepared it by heatingarsenic trifluoride andthiophosphoryl chloride together in a sealed glass tube to 150 °C. Also produced in this reaction wassilicon tetrafluoride and phosphorus fluorides. By increasing thePSCl3 the proportion ofPSF3 was increased. They observed the spontaneous inflammability. They also used this method:
3 PbF2 + P2S5 → 3 PbS + 2 PSF3
at 170 °C, and also substituting a mixture of red phosphorus and sulfur, and substitutingbismuth trifluoride.[5]
Another way to preparePSF3 is to add fluoride toPSCl3 usingsodium fluoride in acetonitrile.[8]
A high yield reaction can be used to produce the gas:[citation needed]
PSF3 is unstable against moisture or heat. The pure gas is completely absorbed by alkali solutions, producing the fluoride and athiophosphate (PSO3−3), but stable against CaO. The latter can be used to removeSiF4 orPF3 impurities.[5]
Hot PSF3 reacts with glass, producingSF4, sulfur and elemental phosphorus. If water is present and the glass isleaded, then thehydrofluoric acid andhydrogen sulfide combination produces a blackplumbous sulfide deposit on the inner surface.[5]
In air, PSF3burns spontaneously with a greyish green flame, producing solid white fumes containingSO2 andP2O5. The flame is one of the coldest known. With dry oxygen, combustion may not be spontaneous and the flame is yellow.[5]
Thiophosphoryl difluoride isocyanate can be formed by reactingPSF3 withsilicon tetraisocyanate at 200 °C in an autoclave.[13]
In general, nucleophilic substitution onto thiophosphoryl fluoride is complex, because freefluoride ions tend to induce disproportionation tohexafluorophosphate and dithiodifluorophosphate (PS2F−2).[10][14] For example, withcesium fluoride:[15]
One fluorine can be substituted by iodine to give thiophosphoryl difluoride iodide,PSIF2.[19]PSIF2 can be converted to hydrothiophosphoryldifluoride,S=PHF2, by reducing it withhydrogen iodide.[20] InF2P(=S)−S−PF2, one sulfur forms a bridge between two phosphorus atoms.[19]
Dimethylaminothiophosphoryl difluoride ((H3C−)2N−P(=S)F2) is a foul smelling liquid with a boiling point of 117 °C. It has aTrouton constant (entropy of vaporization at the boiling point of the liquid) of 24.4, and aheat of evaporation of 9530 cal/mole. Alternately it can be produced byfluorination of dimethylaminothiophosphoryl dichloride ((H3C−)2N−P(=S)Cl2).
The thiophosphoryl trifluoride molecule shape has been determined using electron diffraction. The interatomic distances are P=S 0.187±0.003 nm,P−F 0.153±0.002 nm and bond angles ofF−P−F bonding is 100.3±2°, Themicrowave rotational spectrum has been measured for several differentisotopologues.[21]
Theenthalpy of vaporisation 19.6 kJ/mol at boiling point.[23] The enthalpy of vaporisation at other temperatures is a function of temperature T: H(T)=28.85011(346-T)0.38 kJ/mol.[24]
The molecule is polar. It has a non-uniform distribution of positive and negative charge which gives it adipole moment. When anelectric field is applied more energy is stored than if the molecules did not respond by rotating. This increases thedielectric constant. The dipole moment of one molecule of thiophosphoryl trifluoride is 0.640Debye.[25]
Theinfrared spectrum includesvibrations at 275, 404, 442, 698, 951 and 983 cm−1.[26] These can be used to identify the molecule.
^Padma, D. K.; Vijayalakshmi, S. K.; Vasudevamurthy, A. R. (1976). "Investigations on the preparation, oxidation and reduction reactions of thiophosphoryl fluoride".Journal of Fluorine Chemistry.8 (6): 461.doi:10.1016/S0022-1139(00)81660-7.
^abcdHagen, Arnulf P.; Callaway, Bill W. (1978). "High-pressure reactions of small covalent molecules. 10. The reaction of phosphorus trifluoride with hydrogen sulfide and sulfur dioxide".Inorganic Chemistry.17 (3): 554.doi:10.1021/ic50181a007.
^abcAlmasi, Lucreţia (1971). "The Sulfur–Phosphorus Bond". In Senning, Alexander (ed.).Sulfur in Organic and Inorganic Chemistry. Vol. 1. New York: Marcel Dekker. pp. 79, 81.ISBN0-8247-1615-9.LCCN70-154612. Note the typo on p. 81: the final species in the final display should be PS2F− 2.
^Sampath Kumar, H.P.; Padma, D.K.; Vasudeva Murthy, A.R. (1984). "Reaction of thiophosphoryl fluoride with sulphur trioxide".Journal of Fluorine Chemistry.26:117–123.doi:10.1016/S0022-1139(00)85125-8.
^Sampath Kumar, H.P.; Padma, D.K. (1990). "Reaction of phosphorus trifluoride and thiophosphoryl fluoride with iodine monochloride and oxidation of phosphorus trifluoride with nitryl chloride, iodic acid, periodic acid, sodium nitrite and potassium nitrite".Journal of Fluorine Chemistry.49 (3): 301.doi:10.1016/S0022-1139(00)85026-5.
^Roesky, H.W. (1970). "Thiophosphoryl-difluoride-isocyanate".Journal of Inorganic and Nuclear Chemistry.32 (6):1845–1846.doi:10.1016/0022-1902(70)80591-7.
^Islam, Mohammad Q.; Hill, William E.; Webb, Thomas R. (1990). "Quadruply bonded dimolybdenum complexes of PF2S2−. Comparison with complexes of PR2S2p− (R = Et, Me)".Journal of Fluorine Chemistry.48 (3): 429.doi:10.1016/S0022-1139(00)80227-4.
^Roesky, Herbert W.; Tebbe, Fred N.; Muetterties, Earl L. (1970). "Thiophosphate chemistry. Anion set X2PS2−, (XPS2)2S2−, and (XPS2)2S22−".Inorganic Chemistry.9 (4): 831.doi:10.1021/ic50086a028.
^Padma, D.K.; Vijayalakshmi, S.K. (1978). "Thiophosphoryl fluoride and phosphoryl fluoride as initiators for the polymerisation of tetrahydrofuran".Journal of Fluorine Chemistry.11:51–56.doi:10.1016/S0022-1139(00)81597-3.
^Rhyne, T; Dillard, J (1971). "Reactions of gaseous inorganic negative ions: III. SF6− with POF3 and PSF3".International Journal of Mass Spectrometry and Ion Physics.7 (5): 371.Bibcode:1971IJMSI...7..371R.doi:10.1016/0020-7381(71)85003-9.
^abCharlton, Thomas L.; Cavell, Ronald G. (1969). "Difluorothiophosphoryl-μ-thio-difluorophosphine and difluorophosphoryl-μ-oxo-difluorophosphine. Novel mixed-valence fluorophosphorus compounds".Inorganic Chemistry.8 (11): 2436.doi:10.1021/ic50081a037.
^Charlton, Thomas L.; Cavell, R. G. (1968). "Preparation and properties of iodothiophosphoryl difluoride, SPF2I".Inorganic Chemistry.7 (11): 2195.doi:10.1021/ic50069a005.
^Williams, Quitman; Sheridan, John; Gordy, Walter (1952). "Microwave Spectra and Molecular Structures of POF3, PSF3, POCl3, and PSCl3".The Journal of Chemical Physics.20 (1):164–167.Bibcode:1952JChPh..20..164W.doi:10.1063/1.1700162.
^Handbook of Chemistry and Physics 87 ed page 6-39
Humphries, C. M.; Walsh, A. D.; Warsop, P. A. (1963). "Absorption spectrum of chlorine dioxide in the vacuum ultra-violet".Transactions of the Faraday Society.35: 137.doi:10.1039/df9633500137.
Montana, Anthony J.; Zumbulyadis, Nikolaos; Dailey, Benjamin P. (1976). "19F and 31P magnetic shielding anisotropies and the F–P–F bond angle of PSF3 in a smectic liquid crystal solvent".The Journal of Chemical Physics.65 (11): 4756.Bibcode:1976JChPh..65.4756M.doi:10.1063/1.432929.
Williams, Quitman; Sheridan, John; Gordy, Walter (1952). "Microwave Spectra and Molecular Structures of POF3, PSF3, POCl3, and PSCl3".The Journal of Chemical Physics.20 (1):164–167.Bibcode:1952JChPh..20..164W.doi:10.1063/1.1700162.
Lange, Willy; Askitopoulos, Konstantin (1938). "Zur Kenntnis des Phosphorsulfotrifluorids PSF3 und über ein Salz der Thiodifluorphosphorsäure H\PSF2O]".Berichte der Deutschen Chemischen Gesellschaft (A and B Series).71 (4): 801.doi:10.1002/cber.19380710419.
