Chlorine pentafluoride

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Chlorine pentafluoride
Chlorine-pentafluoride-2D-dimensions.png Chlorine-pentafluoride-3D-balls.png
Chlorine-pentafluoride-3D-vdW.png
Identifiers
CAS number 13637-63-3 YesY
PubChem 61654
RTECS number FO2975000
Jmol-3D images Image 1
Properties
Molecular formula ClF5
Molar mass 130.445 g mol−1
Appearance colorless gas
Density 4.5 g/cm3
Melting point −103 °C (−153 °F; 170 K)
Boiling point −13.1 °C (8.4 °F; 260.0 K)
Solubility in water hydrolyzes
Structure
Molecular shape Square pyramidal
Thermochemistry
Std molar
entropy
So298
310.73 J K−1 mol−1
Std enthalpy of
formation
ΔfHo298
−238.49 kJ mol−1
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Chlorine pentafluoride is an interhalogen compound with formula ClF5. This colourless gas is an strong oxidant that was once a candidate oxidizer for rockets. The molecule adopts a square pyramidal structure with C4v symmetry,[1] as confirmed by its high resolution 19F NMR spectrum.[2]

Preparation[edit]

Some of the earliest research on the preparation was classified.[3][4] It was first prepared by fluorination of chlorine trifluoride at high temperatures and high pressures:

ClF3 + F2 → ClF5

NiF2 catalyzes this reaction.[5]

Certain metal fluorides, MClF4 (i.e. KClF4, RbClF4, CsClF4) react with F2 to produce ClF5 and the corresponding alkali metal fluoride.[4]

Reactions[edit]

In a highly exothermic reaction, water hydrolyses ClF5 to produce chloryl fluoride and hydrogen fluoride:[6]

ClF
5
+ 2 H
2
O
FClO
2
+ 4 HF

It is also a strong fluorinating agent. At room temperature it reacts readily with all elements except noble gases, nitrogen, oxygen and fluorine.[2]

See also[edit]

References[edit]

  1. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 833. ISBN 0080379419. 
  2. ^ a b Pilipovich, D., Maya, W., Lawton, E.A., Bauer, H.F., Sheehan, D. F., Ogimachi, N. N., Wilson, R. D., Gunderloy, F. C., Bedwell, V. E. (1967). "Chlorine pentafluoride. Preparation and Properties". Inorganic Chemistry 6 (10): 1918. doi:10.1021/ic50056a036. 
  3. ^ Clark, John (1972). Ignition! An Informal History of Liquid Rocket Propellants. Rutgers University Press. pp. 87–88. ISBN 0-8135-0725-1. 
  4. ^ a b Smith D. F. (1963). "Chlorine Pentafluoride". Science 141 (3585): 1039–1040. doi:10.1126/science.141.3585.1039. PMID 17739492. 
  5. ^ Šmalc, A., Žemva, B., Slivnik, J., and Lutar K. (1981). "On the Synthesis of Chlorine Pentafluoride". Journal of Fluorine Chemistry 17 (4): 381–383. doi:10.1016/S0022-1139(00)81783-2. 
  6. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 834. ISBN 0080379419. 

External links[edit]