Dichlorine monoxide

Dichlorine monoxide
Dichlorine monoxide
CAS number 7791-21-1
PubChem 24646
ChemSpider 23048 YesY
ChEBI CHEBI:30198 YesY
Jmol-3D images Image 1
Molecular formula Cl2O
Molar mass 86.9054 g/mol
Melting point

−120.6 °C, 153 K, -185 °F

Boiling point

2.2 °C, 275 K, 36 °F

Solubility in water very soluble, hydrolyses 143g Cl2O per 100g water[1]
Solubility in other solvents soluble in CCl4
Dipole moment 0.78 ± 0.08 D
Std enthalpy of
+80.3 kJ mol−1
Standard molar
265.9 J K−1 mol−1
NFPA 704
NFPA 704.svg
Related compounds
Related oxides H2O
 YesY monoxide (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dichlorine monoxide, Cl2O, also known as, oxygen dichloride, dichlorine oxide or chlorine(I) oxide is a chlorine oxide. It is a brownish yellow gas at room temperature which can explode in high concentrations when heated or sparked.[2]

It is best prepared by treating fresh yellow mercury(II) oxide with Cl2 gas:

2 Cl2 + 2 HgO → HgCl2·HgO + Cl2O

It can also be prepared by reaction of Cl2 gas with moist sodium carbonate, Na2CO3. Dichlorine monoxide is very water soluble[1] and is the anhydride of hypochlorous acid. The equilibrium between HOCl and Cl2O in water is reversible[3]

2HOCl <> Cl2O + H2O K(0°C) =3.55x10-3dm3mol-1

Much of the Cl2O manufactured industrially is used to make hypochlorites. It is also the decomposition product of calcium hypochlorite.[citation needed]

The shape of dichlorine monoxide is bent, due to the two lone pairs of electrons orbiting the nucleus that are not used to bond with the chlorine atoms on the oxygen atom.

It contains 42 electrons. 17 electrons of Cl x2 and 8 electrons of O x 1.


  1. ^ a b Inorganic chemistry , Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman , "Dichlorine oxide" p.459 , section 5.3.1 google books link
  2. ^ N. N. Greenwood and A. Earnshaw, "Chemistry of the Elements", 2006 Butterworth-Heinemann
  3. ^ Inorganic chemistry , Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman , "Hypochlorous acid" p.442 , section 4.3.1

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Chlorine monoxide — This article is about the compound ClO. For the oxoanion with the formula ClO−, see hypochlorite. For the molecule Cl2O, see Dichlorine monoxide. Chlorine monoxide …   Wikipedia

  • Chlorine oxide — Chlorine and oxygen can bond in many different ways: chlorine monoxide (ClO) chlorine dioxide (ClO2) chlorine trioxide (ClO3) dichlorine monoxide (Cl2O) dichlorine dioxide (Cl2O2) dichlorine trioxide (Cl2O3) dichlorine tetroxide, also known as… …   Wikipedia

  • Chlorine — This article is about the chemical element. For the bleach, see Sodium hypochlorite. For the upcoming film, see Chlorine (film). sulfur ← chlorine → argon F ↑ Cl ↓ Br …   Wikipedia

  • Hypochlorous acid — Hypochlorous acid …   Wikipedia

  • Chlorine nitrate — Chlorine nitrate …   Wikipedia

  • Selenium tetrachloride — Chembox new Name = Selenium tetrachloride ImageFile = ImageSize = ImageName = IUPACName = Selenium tetrachloride OtherNames = Section1 = Chembox Identifiers CASNo = 10026 03 6 RTECS = VS7875000 PubChem = 24859372 Section2 = Chembox Properties… …   Wikipedia

  • chlorine — chlorinous, adj. /klawr een, in, klohr /, n. a halogen element, a heavy, greenish yellow, incombustible, water soluble, poisonous gas that is highly irritating to the respiratory organs, obtained chiefly by electrolysis of sodium chloride brine:… …   Universalium

  • Oxide — Oxides, such as iron(III) oxide or rust, which consists of hydrated iron(III) oxides Fe2O3·nH2O and iron(III) oxide hydroxide (FeO(OH), Fe(OH)3), form when oxygen combines with other elements An oxide ( …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.