Chlorine pentafluoride

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Chlorine pentafluoride
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Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.734 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
RTECS number
  • FO2975000
UNII
  • InChI=1S/ClF5/c2-1(3,4,5)6 X mark.svgN
    Key: KNSWNNXPAWSACI-UHFFFAOYSA-N X mark.svgN
  • FCl(F)(F)(F)F
Properties
ClF5
Molar mass 130.445 g mol−1
Appearancecolorless gas
Density 4.5 kg/m3 (g/L)
Melting point −103 °C (−153 °F; 170 K)
Boiling point −13.1 °C (8.4 °F; 260.0 K)
Hydrolyzes
Structure
Square pyramidal
Thermochemistry
Std molar
entropy (S⦵298)
310.73 J K−1 mol−1
−238.49 kJ mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Chlorine pentafluoride is an interhalogen compound with formula ClF5. This colourless gas is a 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] It was first synthesized in 1963. [3]

Contents

Preparation

Some of the earliest research on the preparation was classified. [4] [5] It was first prepared by fluorination of chlorine trifluoride at high temperatures and high pressures: [4]

ClF3 + F2 → ClF5
ClF + 2F2 → ClF5
Cl2 + 5F2 → 2ClF5
CsClF4 + F2 → CsF + ClF5

NiF2 catalyzes this reaction. [6]

Certain metal fluorides, MClF4 (i.e. KClF4, RbClF4, CsClF4), react with F2 to produce ClF5 and the corresponding alkali metal fluoride. [5]

Reactions

In a highly exothermic reaction, ClF5 reacts with water to produce chloryl fluoride and hydrogen fluoride: [7]

ClF
5 + 2 H
2O → ClO
2F + 4 HF

It is also a strong fluorinating agent. At room temperature it reacts readily with all elements (including otherwise "inert" elements like platinum and gold) except noble gases, nitrogen, oxygen and fluorine. [2]

Uses

Rocket propellant

Chlorine pentafluoride was once considered for use as an oxidizer for rockets. As a propellant, it has a higher maximum specific impulse than ClF3, but with the same difficulties in handling. [4] Due to the hazardous nature of chlorine pentafluoride, it has yet to be used in a large scale rocket propulsion system.

See also

Related Research Articles

In chemistry, an interhalogen compound is a molecule which contains two or more different halogen atoms and no atoms of elements from any other group.

Chlorine trifluoride is an interhalogen compound with the formula ClF3. It is a colorless, poisonous, corrosive, and extremely reactive gas that condenses to a pale-greenish yellow liquid, the form in which it is most often sold. It is famous for its extreme oxidation properties. The compound is primarily of interest in plasmaless cleaning and etching operations in the semiconductor industry, in nuclear reactor fuel processing, historically as a component in rocket fuels, and various other industrial operations owing to its corrosive nature.

<span class="mw-page-title-main">Bromine trifluoride</span> Chemical compound

Bromine trifluoride is an interhalogen compound with the formula BrF3. At room temperature, it is a straw-coloured liquid with a pungent odor which decomposes violently on contact with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride (UF6) in the processing and reprocessing of nuclear fuel.

<span class="mw-page-title-main">Bromine pentafluoride</span> Chemical compound

Bromine pentafluoride, BrF5, is an interhalogen compound and a fluoride of bromine. It is a strong fluorinating agent.

Iodine pentafluoride is an interhalogen compound with chemical formula IF5. It is one of the fluorides of iodine. It is a colorless liquid, although impure samples appear yellow. It is used as a fluorination reagent and even a solvent in specialized syntheses.

<span class="mw-page-title-main">Cobalt(III) fluoride</span> Chemical compound

Cobalt(III) fluoride is the inorganic compound with the formula CoF3. Hydrates are also known. The anhydrous compound is a hygroscopic brown solid. It is used to synthesize organofluorine compounds.

Antimony pentafluoride is the inorganic compound with the formula SbF5. This colourless, viscous liquid is a strong Lewis acid and a component of the superacid fluoroantimonic acid, formed upon mixing liquid HF with liquid SbF5 in 1:1 ratio. It is notable for its strong Lewis acidity and the ability to react with almost all known compounds.

<span class="mw-page-title-main">Sulfur tetrafluoride</span> Chemical compound

Sulfur tetrafluoride is the chemical compound with the formula SF4. It is a colorless corrosive gas that releases dangerous HF upon exposure to water or moisture. Despite these unwelcome characteristics, this compound is a useful reagent for the preparation of organofluorine compounds, some of which are important in the pharmaceutical and specialty chemical industries.

<span class="mw-page-title-main">Selenium tetrafluoride</span> Chemical compound

Selenium tetrafluoride (SeF4) is an inorganic compound. It is a colourless liquid that reacts readily with water. It can be used as a fluorinating reagent in organic syntheses (fluorination of alcohols, carboxylic acids or carbonyl compounds) and has advantages over sulfur tetrafluoride in that milder conditions can be employed and it is a liquid rather than a gas.

Bromine compounds are compounds containing the element bromine (Br). These compounds usually form the -1, +1, +3 and +5 oxidation states. Bromine is intermediate in reactivity between chlorine and iodine, and is one of the most reactive elements. Bond energies to bromine tend to be lower than those to chlorine but higher than those to iodine, and bromine is a weaker oxidising agent than chlorine but a stronger one than iodine. This can be seen from the standard electrode potentials of the X2/X− couples (F, +2.866 V; Cl, +1.395 V; Br, +1.087 V; I, +0.615 V; At, approximately +0.3 V). Bromination often leads to higher oxidation states than iodination but lower or equal oxidation states to chlorination. Bromine tends to react with compounds including M–M, M–H, or M–C bonds to form M–Br bonds.

<span class="mw-page-title-main">Antimony trifluoride</span> Chemical compound

Antimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swarts' reagent, it is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid. As well as some industrial applications, it is used as a reagent in inorganic and organofluorine chemistry.

<span class="mw-page-title-main">Gold(III) fluoride</span> Chemical compound

Gold(III) fluoride, AuF3, is an orange solid that sublimes at 300 °C. It is a powerful fluorinating agent. It is very sensitive to moisture, yielding gold(III) hydroxide and hydrofluoric acid.

Arsenic trifluoride is a chemical compound of arsenic and fluorine with the chemical formula AsF3. It is a colorless liquid which reacts readily with water.

Arsenic pentafluoride is a chemical compound of arsenic and fluorine. It is a toxic, colorless gas. The oxidation state of arsenic is +5.

Chromium pentafluoride is the inorganic compound with the chemical formula CrF5. It is a red volatile solid that melts at 34 °C. It is the highest known chromium fluoride, since the hypothetical chromium hexafluoride has not yet been synthesized.

Polyhalogen ions are a group of polyatomic cations and anions containing halogens only. The ions can be classified into two classes, isopolyhalogen ions which contain one type of halogen only, and heteropolyhalogen ions with more than one type of halogen.

<span class="mw-page-title-main">Neptunium(VI) fluoride</span> Chemical compound

Neptunium(VI) fluoride (NpF6) is the highest fluoride of neptunium, it is also one of seventeen known binary hexafluorides. It is an orange volatile crystalline solid. It is relatively hard to handle, being very corrosive, volatile and radioactive. Neptunium hexafluoride is stable in dry air but reacts vigorously with water.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

<span class="mw-page-title-main">Terbium(IV) fluoride</span> Chemical compound

Terbium(IV) fluoride is an inorganic compound with a chemical formula TbF4. It is a white solid that is a strong oxidizer. It is also a strong fluorinating agent, emitting relatively pure atomic fluorine when heated, rather than the mixture of fluoride vapors emitted from cobalt(III) fluoride or cerium(IV) fluoride.

<span class="mw-page-title-main">Protactinium(V) fluoride</span> Chemical compound

Protactinium(V) fluoride is a fluoride of protactinium with the chemical formula PaF5.

References

  1. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 833. ISBN   978-0-08-037941-8.
  2. 1 2 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. ↑ Smith D. F. (1963). "Chlorine Pentafluoride". Science . 141 (3585): 1039–1040. Bibcode:1963Sci...141.1039S. doi:10.1126/science.141.3585.1039. PMID   17739492. S2CID   39767609.
  4. 1 2 3 Clark, John Drury (23 May 2018). Ignition!: An Informal History of Liquid Rocket Propellants. Rutgers University Press. pp. 87–88. ISBN   978-0-8135-9918-2.
  5. 1 2 Smith D. F. (1963). "Chlorine Pentafluoride". Science . 141 (3585): 1039–1040. Bibcode:1963Sci...141.1039S. doi:10.1126/science.141.3585.1039. PMID   17739492. S2CID   39767609.
  6. ↑ Šmalc A, Žemva B, Slivnik J, 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.
  7. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 834. ISBN   978-0-08-037941-8.
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