Dichlorine monoxide

Not to be confused with chlorine monoxide.

Dichlorine monoxide

Names
IUPAC name

Oxygen dichloride

Systematic IUPAC name

Dichloridooxygen
Dichlorooxidane

Other names

Dichlorine (mon)oxide
Chlorine(I) oxide
Hypochlorous oxide
Hypochlorous anhydride
Chloro hypochlorite

Identifiers

CAS Number

* 7791-21-1 Y

3D model (JSmol)

* Interactive image

ChEBI |

* CHEBI:30198 Y

ChemSpider |

* 23048 Y

PubChem CID

* 24646

UNII |

* 0EQ5I4TK19 Y

InChI

* InChI=1S/Cl2O/c1-3-2 Y

Key: RCJVRSBWZCNNQT-UHFFFAOYSA-N Y

* InChI=1/Cl2O/c1-3-2

Key: RCJVRSBWZCNNQT-UHFFFAOYAA

SMILES

* ClOCl

Properties

Chemical formula

| Cl2O
Molar mass | 86.9054 g/mol
Appearance  | brownish-yellow gas
Melting point |  −120.6 °C (−185.1 °F; 152.6 K)
Boiling point |  2.0 °C (35.6 °F; 275.1 K)

Solubility in water

| very soluble, hydrolyses 143 g Cl2O per 100 g water
Solubility in other solvents  | soluble in CCl4
Structure

Dipole moment

| 0.78 ± 0.08 D
Thermochemistry

Std molar
entropy (S ~~o~~ 298)

| 265.9 J K−1 mol−1

Std enthalpy of
formation (ΔfH⦵298)

| +80.3 kJ mol−1
Hazards
Safety data sheet | [1]
GHS pictograms |
GHS Signal word | DANGER

GHS hazard statements

| H290, H314, H400, H411

GHS precautionary statements

| P234, P260, P264, P273, P280, P301+330+331, P303+361+353, P304+340, P305+351+338, P310, P311, P321, P363, P390, P391, P405, P406, P501
NFPA 704 (fire diamond)  |

Related compounds

Other cations

* Water
* Dibromine monoxide
* Diiodine monoxide

Related compounds

| Oxygen difluoride, nitrous oxide, chlorine dioxide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)
Infobox references

Tracking categories (test):

* SizeSet

Dichlorine monoxide (IUPAC name: oxygen dichloride) is an inorganic compound with the molecular formula Cl2O. It was first synthesised in 1834 by Antoine Jérôme Balard,[2] who along with Gay-Lussac also determined its composition. In older literature it is often referred to as chlorine monoxide,[3] which can be a source of confusion as that name now refers to the ClO• radical.

At room temperature it exists as a brownish-yellow gas which is soluble in both water and organic solvents. Chemically, it is a member of the chlorine oxide family of compounds, as well as being the anhydride of hypochlorous acid. It is a strong oxidiser and chlorinating agent.

## Contents

* 1 Preparation
* 2 Structure
* 3 Reactions
* 3.1 With inorganic compounds
* 3.2 With organic compounds
* 3.3 Photochemistry
* 3.4 Explosive properties
* 4 References

## Preparation

The earliest method of synthesis was to treat mercury(II) oxide with chlorine gas.[3] However, this method is expensive, as well as highly dangerous due to the risk of mercury poisoning.

2 Cl2 \+ HgO → HgCl2 \+ Cl2O

A safer and more convenient method of production is the reaction of chlorine gas with hydrated sodium carbonate at 20–30 °C.[3]

2 Cl2 \+ 2 Na2CO3 \+ H2O → Cl2O + 2 NaHCO3 \+ 2 NaCl

2 Cl2 \+ 2 NaHCO3 → Cl2O + 2 CO2 \+ 2 NaCl + H2O

This reaction can be performed in the absence of water but requires heating to 150–250 °C; as dichlorine monoxide is unstable at these temperatures[4] it must therefore be continuously removed to prevent thermal decomposition.

2 Cl2 \+ Na2CO3 → Cl2O + CO2 \+ 2 NaCl

## Structure

The structure of dichlorine monoxide is similar to that of water and hypochlorous acid, with the molecule adopting a bent molecular geometry (due to the lone pairs on the oxygen atom) and resulting in C2V molecular symmetry. The bond angle is slightly larger than normal, likely due to steric repulsion between the bulky chlorine atoms.

*   *   *

In the solid state, it crystallises in the tetrahedral space group I41/amd, making it isostructural to the high pressure form of water, ice VIII.[5]

## Reactions

Dichlorine monoxide is highly soluble in water,[6] where it exists in an equilibrium with HOCl. The rate of hydrolysis is slow enough to allow the extraction of Cl2O with organic solvents such as CCl4,[3] but the equilibrium constant ultimately favours the formation of hypochlorous acid.[7]

2 HOCl ⇌ Cl2O + H2O K (0 °C) = 3.55x10−3 dm3/mol

Despite this, it has been suggested that dichlorine monoxide may be the active species in the reactions of HOCl with olefins and aromatic compounds,[8][9] as well as in the chlorination of drinking water.[10]

### With inorganic compounds

Dichlorine monoxide reacts with metal halides, with the loss of Cl2, to form unusual oxyhalides.[11][12][3]

VOCl3 \+ Cl2O → VO2Cl + 2 Cl2
TiCl4 \+ Cl2O → TiOCl2 \+ 2 Cl2
SbCl5 \+ 2 Cl2O → SbO2Cl + 4 Cl2

Similar reactions have also been observed with certain inorganic halides.[13][14]

AsCl3 \+ 2 Cl2O → AsO2Cl + 3 Cl2
NOCl + Cl2O → NO2Cl + Cl2

### With organic compounds

Dichlorine monoxide is an effective chlorinating agent. It can be used for either the side-chain or ring chlorination of deactivated aromatic substrates.[15] For activated aromatics such as phenols and aryl-ethers it primarily reacts to give ring halogenated products.[16] It has been suggested that dichlorine monoxide may be the active species in the reactions of HOCl with olefins and aromatic compounds.[8][9]

### Photochemistry

Dichlorine monoxide undergoes photodissociation, eventually forming O2 and Cl2. The process is primarily radical based, with flash photolysis showing radical hypochlorite (ClO·) to be a key intermediate.[17]

2 Cl2O → 2 Cl2 \+ O2

### Explosive properties

Dichlorine monoxide is explosive, although there is a lack of modern research into this behaviour. Room temperature mixtures with oxygen could not be detonated by an electric spark until they contained at least 23.5% Cl2O[18] which is an exceedingly high minimum explosive limit. There are conflicting reports of it exploding on exposure to strong light.[19][20] Heating above 120 °C, or a rapid rate of heating at lower temperatures also apparently lead to explosions.[3] Liquid dichlorine monoxide has been reported to be shock-sensitive.[21]

## References

1. ↑ "CHLORINE MONOXIDE". National Oceanic and Atmospheric Administration. http://cameochemicals.noaa.gov/chemical/18051.
2. ↑ Balard, A.J. (1834). "Recherches sur la nature des combinaisons décolorantes du chlore" (in fr). Annales de Chimie et de Physique. 2nd series 57: 225–304. https://babel.hathitrust.org/cgi/pt?id=ien.35556014128060;view=1up;seq=230.
3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 Renard, J. J.; Bolker, H. I. (1 August 1976). "The chemistry of chlorine monoxide (dichlorine monoxide)". Chemical Reviews 76 (4): 487–508. doi:10.1021/cr60302a004.
4. ↑ Hinshelwood, Cyril Norman; Prichard, Charles Ross (1923). "CCCXIII.—A homogeneous gas reaction. The thermal decomposition of chlorine monoxide. Part I". Journal of the Chemical Society, Transactions 123: 2730–2738. doi:10.1039/CT9232302730.
5. ↑ Minkwitz, R.; Bröchler, R.; Borrmann, H. (1 January 1998). "Tieftemperatur-Kristallstruktur von Dichlormonoxid, Cl2O". Zeitschrift für Kristallographie 213 (4): 237–239. doi:10.1524/zkri.1998.213.4.237. Bibcode: 1998ZK....213..237M.
6. ↑ Davis, D. S. (1942). "Nomograph for the Solubility of Chlorine Monoxide in Water". Industrial & Engineering Chemistry 34 (5): 624. doi:10.1021/ie50389a021.
7. ↑ Aylett, founded by A.F. Holleman; continued by Egon Wiberg; translated by Mary Eagleson, William Brewer; revised by Bernhard J. (2001). Inorganic chemistry (1st English ed., [edited] by Nils Wiberg. ed.). San Diego, Calif. : Berlin: Academic Press, W. de Gruyter.. p. 442. ISBN 9780123526519.
8. ↑ 8.0 8.1 Swain, C. Gardner; Crist, DeLanson R. (1 May 1972). "Mechanisms of chlorination by hypochlorous acid. The last of chlorinium ion, Cl+". Journal of the American Chemical Society 94 (9): 3195–3200. doi:10.1021/ja00764a050. Bibcode: 1972JAChS..94.3195S.
9. ↑ 9.0 9.1 Sivey, John D.; McCullough, Corey E.; Roberts, A. Lynn (1 May 2010). "Chlorine Monoxide (Cl2O) and Molecular Chlorine (Cl2) as Active Chlorinating Agents in Reaction of Dimethenamid with Aqueous Free Chlorine". Environmental Science & Technology 44 (9): 3357–3362. doi:10.1021/es9038903. PMID 20302364. Bibcode: 2010EnST...44.3357S.
10. ↑ Powell, Steven C. (1 May 2010). "The active species in drinking water chlorination: the case for Cl2O". Environmental Science & Technology 44 (9): 3203. doi:10.1021/es100800t. PMID 20302368. Bibcode: 2010EnST...44.3203P.
11. ↑ Oppermann, H. (1967). "Untersuchungen an Vanadinoxidchloriden und Vanadinchloriden. I. Gleichgewichte mit VOCl3, VO2Cl und VOCl2". Zeitschrift für anorganische und allgemeine Chemie 351 (3–4): 113–126. doi:10.1002/zaac.19673510302.
12. ↑ Dehnicke, Kurt (1961). "Titan(IV)-Oxidchlorid TiOCl2". Zeitschrift für anorganische und allgemeine Chemie 309 (5–6): 266–275. doi:10.1002/zaac.19613090505.
13. ↑ Dehnicke, Kurt (1 December 1964). "Über die Oxidchloride PO2Cl, AsO2Cl und SbO2Cl". Chemische Berichte 97 (12): 3358–3362. doi:10.1002/cber.19640971215.
14. ↑ Martin, H. (1 January 1966). "Kinetic Relationships between Reactions in the Gas Phase and in Solution". Angewandte Chemie International Edition in English 5 (1): 78–84. doi:10.1002/anie.196600781.
15. ↑ Marsh, F. D.; Farnham, W. B.; Sam, D. J.; Smart, B. E. (1 August 1982). "Dichlorine monoxide: a powerful and selective chlorinating reagent". Journal of the American Chemical Society 104 (17): 4680–4682. doi:10.1021/ja00381a032. Bibcode: 1982JAChS.104.4680M.
16. ↑ Sivey, John D.; Roberts, A. Lynn (21 February 2012). "Assessing the Reactivity of Free Chlorine Constituents Cl2, Cl2O, and HOCl Toward Aromatic Ethers". Environmental Science & Technology 46 (4): 2141–2147. doi:10.1021/es203094z. PMID 22211432. Bibcode: 2012EnST...46.2141S.
17. ↑ Basco, N.; Dogra, S. K. (22 June 1971). "Reactions of Halogen Oxides Studied by Flash Photolysis. II. The Flash Photolysis of Chlorine Monoxide and of the ClO Free Radical". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 323 (1554): 401–415. doi:10.1098/rspa.1971.0112. Bibcode: 1971RSPSA.323..401B.
18. ↑ Cady, George H.; Brown, Robert E. (September 1945). "Minimum Explosive Concentration of Chlorine Monoxide Diluted with Oxygen". Journal of the American Chemical Society 67 (9): 1614–1615. doi:10.1021/ja01225a501. Bibcode: 1945JAChS..67.1614C.
19. ↑ Iredale, T.; Edwards, T. G. (April 1937). "Photoreaction of Chlorine Monoxide and Hydrogen". Journal of the American Chemical Society 59 (4): 761. doi:10.1021/ja01283a504. Bibcode: 1937JAChS..59..761I.
20. ↑ Wallace, Janet I.; Goodeve, C. F. (1 January 1931). "The heats of dissociation of chlorine monoxide and chlorine dioxide". Transactions of the Faraday Society 27: 648. doi:10.1039/TF9312700648.
21. ↑ Pilipovich, Donald; Lindahl, C. B.; Schack, Carl J.; Wilson, R. D.; Christe, Karl O. (1972). "Chlorine trifluoride oxide. I. Preparation and properties". Inorganic Chemistry 11 (9): 2189–2192. doi:10.1021/ic50115a040. ISSN 0020-1669.

* v
* t
* e

Chlorine compounds

* ClF
* ClF3
* ClF5
* ClNO3
* ClO
* ClOF3
* Cl2O2
* ClO2
* ClO2F
* ClO3F
* Cl2O
* Cl2O4
* Cl2O6
* Cl2O7
* HCl
* SiCl4

* v
* t
* e

Oxides

Mixed oxidation states|

* Antimony tetroxide (Sb2O4)
* Cobalt(II,III) oxide (Co3O4)
* Europium(II,III) oxide (Eu3O4)
* Iron(II,III) oxide (Fe<sub>3O4)
* Lead(II,IV) oxide (Pb3O4)
* Manganese(II,III) oxide (Mn3O4)
* Silver(I,III) oxide (Ag2O2)
* Triuranium octoxide (U3O8)
* Carbon suboxide (C3O2)
* Mellitic anhydride (C12O9)
* [[Chemistry:Praseodymium(III,IV) Praseodymium(III,IV) oxide]] (Pr6O11)
* Terbium(III,IV) oxide (Tb4O7)

+1 oxidation state|

* Copper(I) oxide (Cu<sub>2O)
* Caesium oxide (Cs2O)
* Dicarbon monoxide (C2O)
* Dichlorine monoxide (Cl2O)
* Gallium(I) oxide (Ga2O)
* Lithium oxide (Li2O)
* Potassium oxide (K2O)
* Rubidium oxide (Rb2O)
* Silver oxide (Ag2O)
* Thallium(I) oxide (Tl2O)
* Sodium oxide (Na2O)
* Water (hydrogen oxide) (H2O)

+2 oxidation state|

* Aluminium(II) oxide (AlO)
* Barium oxide (BaO)
* Beryllium oxide (BeO)
* Cadmium oxide (CdO)
* Calcium oxide (CaO)
* Carbon monoxide (CO)
* Chromium(II) oxide (CrO)
* Cobalt(II) oxide (CoO)
* Copper(II) oxide (CuO)
* Europium(II) oxide (EuO)
* Germanium monoxide (GeO))
* Iron(II) oxide (FeO)
* Lead(II) oxide (PbO)
* Magnesium oxide (MgO)
* Manganese(II) oxide (MnO)
* Mercury(II) oxide (HgO)
* Nickel(II) oxide (NiO)
* Nitric oxide (NO)
* Palladium(II) oxide (PdO)
* Silicon monoxide (SiO)
* Strontium oxide (SrO)
* Sulfur monoxide (SO)
* Disulfur dioxide (S2O2)
* Thorium monoxide (ThO)
* Tin(II) oxide (SnO)
* Titanium(II) oxide (TiO)
* Vanadium(II) oxide (VO)
* Zinc oxide (ZnO)

+3 oxidation state|

* Aluminium oxide (Al<sub>2O3)
* Antimony trioxide (Sb2O3)
* Arsenic trioxide (As2O3)
* Bismuth(III) oxide (Bi2O3)
* Boron trioxide (B2O3)
* Cerium(III) oxide (Ce2O3)
* Dibromine trioxide (Br2O3)
* Chromium(III) oxide (Cr2O3)
* Dinitrogen trioxide (N2O3)
* Dysprosium(III) oxide (Dy2O3)
* Erbium(III) oxide (Er2O3)
* Europium(III) oxide (Eu2O3)
* Gadolinium(III) oxide (Gd2O3)
* Gallium(III) oxide (Ga2O3)
* Holmium(III) oxide (Ho2O3)
* Indium(III) oxide (In<sub>2O3)
* Iron(III) oxide (Fe2O3)
* Lanthanum oxide (La2O3)
* Lutetium(III) oxide (Lu2O3)
* Manganese(III) oxide (Mn2O3)
* Neodymium(III) oxide (Nd2O3)
* Nickel(III) oxide (Ni2O3)
* Phosphorus trioxide (P4O6)
* Praseodymium(III) oxide (Pr2O3)
* Promethium(III) oxide (Pm2O3)
* Rhodium(III) oxide (Rh2O3)
* [[Chemistry:Samarium(III) Samarium(III) oxide]] (Sm2O3)
* Scandium oxide (Sc2O3)
* Terbium(III) oxide (Tb2O3)
* Thallium(III) oxide (Tl2O3)
* Thulium(III) oxide (Tm2O3)
* Titanium(III) oxide (Ti2O3)
* Tungsten(III) oxide (W2O3)
* Vanadium(III) oxide (V2O3)
* Ytterbium(III) oxide (Yb2O3)
* Yttrium(III) oxide (Y2O3)

+4 oxidation state|

* Americium dioxide (AmO2)
* Carbon dioxide (CO2)
* Carbon trioxide (CO3)
* Cerium(IV) oxide (CeO2)
* Chlorine dioxide (ClO2)
* Chromium(IV) oxide (CrO<sub>2)
* Dinitrogen tetroxide (N2O4)
* Germanium dioxide (GeO<sub>2)
* [[Chemistry:Hafnium(IV) Hafnium(IV) oxide]] (HfO2)
* Lead dioxide (PbO2)
* Manganese dioxide (MnO2)
* Neptunium(IV) oxide (NpO2)
* Nitrogen dioxide (NO2)
* Osmium dioxide (OsO2)
* Plutonium(IV) oxide (PuO2)
* Praseodymium(IV) oxide (PrO2)
* Protactinium(IV) oxide (PaO2)
* Rhodium(IV) oxide (RhO2)
* Ruthenium(IV) oxide (RuO<sub>2)
* Selenium dioxide (SeO2)
* Silicon dioxide (SiO2)
* Sulfur dioxide (SO2)
* Tellurium dioxide (TeO<sub>2)
* [[Chemistry:Terbium(IV) Terbium(IV) oxide]] (TbO2)
* Thorium dioxide (ThO2)
* Tin dioxide (SnO2)
* Titanium dioxide (TiO<sub>2)
* Tungsten(IV) oxide (WO2)
* Uranium dioxide (UO2)
* Vanadium(IV) oxide (VO2)
* Zirconium dioxide (ZrO2)

+5 oxidation state|

* Antimony pentoxide (Sb2O5)
* Arsenic pentoxide (As2O5)
* Dinitrogen pentoxide (N2O5)
* Niobium pentoxide (Nb2O5)
* Phosphorus pentoxide (P2O5)
* Protactinium(V) oxide (Pa2O5)
* Tantalum pentoxide (Ta2O5)
* Vanadium(V) oxide (V2O5)

+6 oxidation state|

* Chromium trioxide (CrO3)
* Molybdenum trioxide (MoO3)
* Rhenium trioxide (ReO3)
* Selenium trioxide (SeO3)
* Sulfur trioxide (SO3)
* Tellurium trioxide (TeO3)
* Tungsten trioxide (WO3)
* Uranium trioxide (UO3)
* Xenon trioxide (XeO3)
* Iridium trioxide (IrO3)

+7 oxidation state|

* Dichlorine heptoxide (Cl2O7)
* Manganese heptoxide (Mn2O7)
* [[Chemistry:Rhenium(VII) Rhenium(VII) oxide]] (Re2O7)
* Technetium(VII) oxide (Tc2O7)

+8 oxidation state|

* Osmium tetroxide (OsO4)
* Ruthenium tetroxide (RuO4)
* Xenon tetroxide (XeO4)
* Iridium tetroxide (IrO4)
* Hassium tetroxide (HsO4)

Related|

* Oxocarbon
* Suboxide
* Oxyanion
* Ozonide
* Peroxide
* Superoxide

Oxides are sorted by oxidation state. Category:Oxides

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Dichlorine monoxide. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Chemistry:Dichlorine_monoxide&oldid=4175264"
*[CID]: Compound ID
*[H290]: May be corrosive to metals
*[H314]: Causes severe skin burns and eye damage
*[H400]: Very toxic to aquatic life
*[H411]: Toxic to aquatic life with long lasting effects
*[P234]: Keep only in original container
*[P260]: Do not breathe dust/fume/gas/mist/vapours/spray
*[P264]: Wash … thoroughly after handling
*[P273]: Avoid release to the environment
*[P280]: Wear protective gloves/protective clothing/eye protection/face protection
*[P301+330+331]: IF SWALLOWED: Rinse mouth. Do NOT induce vomiting
*[P303+361+353]: IF ON SKIN (or hair): Remove/Take off immediately all contaminated clothing. Rinse skin with water/shower
*[P304+340]: IF INHALED: Remove victim to fresh air and keep at rest in a position comfortable for breathing
*[P305+351+338]: IF IN EYES: Rinse continuously with water for several minutes. Remove contact lenses if present and easy to do – continue rinsing
*[P310]: Immediately call a POISON CENTER or doctor/physician
*[P311]: Call a POISON CENTER or doctor/physician
*[P321]: Specific treatment (see … on this label)
*[P363]: Wash contaminated clothing before reuse
*[P390]: Absorb spillage to prevent material damage
*[P391]: Collect spillage
*[P405]: Store locked up
*[P406]: Store in a corrosive resistant/… container with a resistant inner liner
*[P501]: Dispose of contents/container to …
*[v]: View this template
*[t]: Discuss this template
*[e]: Edit this template