Dichlorine monoxide
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| Names | |||
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| Other names
Oxygen dichloride
Dichlorine oxide Chlorine(I) oxide Hypochlorous oxide Hypochlorous anhydride | |||
| Identifiers | |||
3D model (JSmol)
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| ChEBI | |||
| ChemSpider | |||
| ECHA InfoCard | 100.029.312 | ||
PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |||
| Cl2O | |||
| Molar mass | 86.9054 g/mol | ||
| Melting point | −120.6 °C (−185.1 °F; 152.6 K) | ||
| Boiling point | 2.2 °C (36.0 °F; 275.3 K) | ||
| very soluble, hydrolyses 143 g Cl2O per 100 g water[1] | |||
| Solubility in other solvents | soluble in CCl4 | ||
| Structure | |||
| 0.78 ± 0.08 D | |||
| Thermochemistry | |||
Std molar
entropy (S⦵298) |
265.9 J K−1 mol−1 | ||
Std enthalpy of
formation (ΔfH⦵298) |
+80.3 kJ mol−1 | ||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Related compounds | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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 exposed to heat or sparks.[2]
Preparation
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]
- 2 HOCl ⇌ Cl2O + H2O K (0 °C) = 3.55x10-3 dm3/mol
Uses
Much of the Cl2O manufactured industrially is used to make hypochlorites. It is also the decomposition product of calcium hypochlorite.[citation needed]
Structure
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.
References
- ^ a b Inorganic chemistry, Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Dichlorine oxide" p.459, section 5.3.1 google books link
- ^ N. N. Greenwood and A. Earnshaw, "Chemistry of the Elements", 2006 Butterworth-Heinemann
- ^ Inorganic chemistry, Egon Wiberg, Nils Wiberg, Arnold Frederick Holleman, "Hypochlorous acid" p.442, section 4.3.1