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Chlorine trifluoride oxide

Names
IUPAC name trifluoro(oxo)-λ5-chlorane
Identifiers
CAS Number	30708-80-6
3D model (JSmol)	Interactive image
PubChem CID	15388485
CompTox Dashboard (EPA)	DTXSID001278020
InChI InChI=1S/ClF3O/c2-1(3,4)5Key: QPKQQPNQDSQNHS-UHFFFAOYSA-N
SMILES O=Cl(F)(F)F
Properties
Chemical formula	ClF3O
Molar mass	108.44 g·mol
Density	1.865
Melting point	−42 °C (−44 °F; 231 K)
Boiling point	29 °C (84 °F; 302 K)
Structure
Crystal structure	monoclinic
Space group	C2/m
Lattice constant	a = 9.826, b = 12.295, c = 4.901α = 90°, β = 90.338°, γ = 90°
Lattice volume (V)	592.1
Formula units (Z)	8
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Related compounds
Related compounds	BrOF3; IOF3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Chlorine oxide trifluoride or chlorine trifluoride oxide is a corrosive liquid molecular compound with formula ClOF₃. It was developed secretly as a rocket fuel oxidiser.

Production

Chlorine oxide trifluoride was originally made at Rocketdyne by treating dichlorine monoxide with fluorine. Other substances that could react with fluorine to make it includes sodium chlorite (NaClO₂), and chlorine nitrate (ClONO₂). The first published production method was a reaction of dichlorine monoxide with oxygen difluoride (OF₂). Yet other production methods are reactions between ClO₂F or ClO₃F and chlorine fluorides. A safer approach is the use chlorine nitrate with fluorine.

Reactions

As a Lewis base it can lose a fluoride ion to Lewis acids, yielding the difluorooxychloronium(V) cation (ClOF₂). Compounds with this include: ClOF₂BF₄, ClOF₂PF₆, ClOF₂AsF₆, ClOF₂SbF₆, ClOF₂BiF₆, ClOF₂VF₆, ClOF₂NbF₆, ClOF₂TaF₆, ClOF₂UF₆, ClOF₂, (ClOF₂)₂SiF₆, ClOF₂MoOF₅, ClOF₂Mo₂O₄F₉, ClOF₂PtF₆.

Functioning as a Lewis acid, it can gain a fluoride ion from a strong base to yield a tetrafluorooxychlorate(V) anion: ClOF₄ ion. These include KClOF₄, RbClOF₄, and CsClOF₄. This allows purification of ClOF₃, as at room temperature a solid complex is formed, but this decomposes between 50 and 70 °C. Other likely impurities either will not react with alkali fluoride, or if they do will not easily decompose.

Chlorine trifluoride oxide fluoridates various materials such as chlorine monoxide, chlorine, glass or quartz. ClOF₃ + Cl₂O → 2ClF + ClO₂F; 2ClOF₃ + 2Cl₂ → 6ClF + O₂ at 200 °C

Chlorine trifluoride oxide adds to chlorine fluorosulfate, ClOF₃ + 2ClOSO₂F → S₂O₅F₂ + FClO₂ + 2ClF. The reaction also produces SO₂F₂.

Chlorine trifluoride oxide can fluoridate and add oxygen in the same reaction, reacting with molybdenum pentafluoride, silicon tetrafluoride, tetrafluorohydrazine (over 100 °C), HNF₂, and F₂NCOF. From HNF₂ the main result was NF₃O. From MoF₅, the results were MoF₆ and MoOF₄.

It reacts explosively with hydrocarbons. With small amounts of water, ClO₂F is formed along with HF.

Over 280 °C ClOF₃ decomposes to oxygen and chlorine trifluoride.

Properties

The boiling point of chlorine trifluoride oxide is 29 °C.

The shape of the molecule is a trigonal bipyramid, with two fluorine atoms at the top and bottom (apex) (F_a) and an electron pair, oxygen and fluorine (F_e) on the equator. The Cl=O bond length is 1.405 Å, Cl-F_e 1.603 Å, other Cl-F_a 1.713 Å, ∠F_eClO=109° ∠F_aClO=95°, ∠F_aClF_e=88°. The molecule is polarised, Cl has a +1.76 charge, O has −0.53, equatorial F has −0.31 and apex F has −0.46. The total dipole moment is 1.74 D.

References

1. Urben, Peter (2017). Bretherick's Handbook of Reactive Chemical Hazards. Elsevier. p. 784. ISBN 9780081010594.
2. Ellern, Arkady; Boatz, Jerry A.; Christe, Karl O.; Drews, Thomas; Seppelt, Konrad (September 2002). "The Crystal Structures of ClF₃O, BrF₃O, and ". Zeitschrift für anorganische und allgemeine Chemie. 628 (9–10): 1991–1999. doi:10.1002/1521-3749(200209)628:9/10<1991::AID-ZAAC1991>3.0.CO;2-1.
3. ^ Advances in Inorganic Chemistry and Radiochemistry. Academic Press. 1976. pp. 331–333. ISBN 9780080578675.
4. ^ Holloway, John H.; Laycock, David (1983). Advances in Inorganic Chemistry. Academic Press. pp. 178–179. ISBN 9780080578767.
5. Christe, Karl O.; Curtis, E. C.; Schack, Carl J. (September 1972). "Chlorine trifluoride oxide. VII. Difluorooxychloronium(V) cation, ClF₂O. Vibrational spectrum and force constants". Inorganic Chemistry. 11 (9): 2212–2215. doi:10.1021/ic50115a046.
6. ^ Schack, Carl J.; Lindahl, C. B.; Pilipovich, Donald.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. IV. Reaction chemistry". Inorganic Chemistry. 11 (9): 2201–2205. doi:10.1021/ic50115a043.
7. ^ Christe, K.O.; Schack, C.J. (1976). Chlorine Oxyfluorides. Advances in Inorganic Chemistry and Radiochemistry. Vol. 18. pp. 319–398. doi:10.1016/S0065-2792(08)60033-3. ISBN 9780120236183.
8. Christe, Karl O.; Schack, Carl J.; Pilipovich, Donald.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. V. Complex formation with Lewis acids and bases". Inorganic Chemistry. 11 (9): 2205–2208. doi:10.1021/ic50115a044.
9. Pilipovich, Donald.; Lindahl, C. B.; Schack, Carl J.; Wilson, R. D.; Christe, Karl O. (September 1972). "Chlorine trifluoride oxide. I. Preparation and properties". Inorganic Chemistry. 11 (9): 2189–2192. doi:10.1021/ic50115a040.
10. Oberhammer, Heinz.; Christe, Karl O. (January 1982). "Gas-phase structure of chlorine trifluoride oxide, ClF₃O". Inorganic Chemistry. 21 (1): 273–275. doi:10.1021/ic00131a050.

• Oxyfluorides
• Chlorine(V) compounds