Dichlorine heptoxide

Dichlorine heptoxide
Names
IUPAC name
Dichlorine heptoxide
Other names
Chlorine(VII) oxide; Perchloric anhydride; (Perchloryloxy)chlorane trioxide
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
UNII
  • InChI=1S/Cl2O7/c3-1(4,5)9-2(6,7)8 checkY
    Key: SCDFUIZLRPEIIH-UHFFFAOYSA-N checkY
  • InChI=1.001/Cl2O7/c3-1(4,5)9-2(6,7)8
    Key: SCDFUIZLRPEIIH-UHFFFAOYAG
  • O=Cl(=O)(=O)OCl(=O)(=O)=O
Properties
Cl2O7
Molar mass 182.901 g/mol
Appearance colorless liquid, colorless gas
Density 1.9 g/cm3
Melting point −91.57 °C (−132.83 °F; 181.58 K)
Boiling point 82.07 °C (179.73 °F; 355.22 K)
hydrolyzes to form perchloric acid
Thermochemistry
275.7 kJ/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 oxidizer, contact explosive[1]
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 3: Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water, or will detonate if severely shocked. E.g. hydrogen peroxideSpecial hazard OX: Oxidizer. E.g. potassium perchlorate
3
0
3
OX
Related compounds
Related compounds
 Manganese heptoxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

Dichlorine heptoxide is the chemical compound with the formula Cl2O7. This chlorine oxide is the anhydride of perchloric acid. It is produced by the careful distillation of perchloric acid in the presence of the dehydrating agent phosphorus pentoxide:[1]

2 HClO4 + P4O10 → Cl2O7 + H2P4O11

The chlorine(VII) oxide can be distilled off from the mixture.

It may also be formed by illumination of mixtures of chlorine and ozone with blue light.[2] It slowly hydrolyzes back to perchloric acid.

  1. ^ a b Holleman, Arnold F.; Wiberg, Egon (2001). Inorganic chemistry. Translated by Mary Eagleson; William Brewer. San Diego: Academic Press. p. 464. ISBN 0-12-352651-5.
  2. ^ Byrns, A. C.; Rollefson, G. K. (1934). "The Formation of Chlorine Heptoxide on Illumination of Mixtures of Chlorine and Ozone". Journal of the American Chemical Society. 56 (5): 1250–1251. doi:10.1021/ja01320a506.