Dichlorine hexoxide

"ClO3" redirects here. For the oxoanion with the formula [ClO₃]⁻, see chlorate.

Dichlorine hexoxide
IUPAC name Dichlorine hexoxide
Other names Chlorine(VI) oxide; Chlorine trioxide; Chloryl perchlorate
Identifiers
CAS number	12442-63-6
Properties
Molecular formula	Cl2O6
Molar mass	166.901 g/mol
Appearance	red liquid
Density	1.65 g/cm3
Melting point	3.5 °C
Boiling point	200 °C
Solubility in water	reacts with water
Hazards
Main hazards	oxidizer
Y hexoxide (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Dichlorine hexoxide is the chemical compound with the formula Cl₂O₆. This chlorine oxide is the mixed anhydride of chloric and perchloric acids. It is produced by reaction between chlorine dioxide and excess ozone:

2 ClO₂ + 2 O₃ → 2 ClO₃ + 2 O₂ → Cl₂O₆ + 2 O₂

It is a dark red fuming liquid at room temperature that crystallizes as an ionic compound, chloryl perchlorate, [ClO₂]⁺[ClO₄]⁻. It was originally reported to exist as the monomeric chlorine trioxide ClO₃ in gas phase,^[1] but was later shown to remain an oxygen-bridged dimer after evaporation and until thermal decomposition into chlorine perchlorate, Cl₂O₄, and oxygen.^[2]

Properties

Cl₂O₆ is diamagnetic and is a very strong oxidizing agent. Although stable at room temperature, it explodes violently on contact with organic compounds^[3] and reacts with gold to produce the chloryl salt [ClO₂]⁺[Au(ClO₄)₄]⁻.^[4] Many other reactions involving Cl₂O₆ reflect its ionic structure, [ClO₂]⁺[ClO₄]⁻, including the following:^[5]

NO₂F + Cl₂O₆ → NO₂ClO₄ + ClO₂F

NO + Cl₂O₆ → NOClO₄ + ClO₂

2 V₂O₅ + 12 Cl₂O₆ → 4 VO(ClO₄)₃ + 12 ClO₂ + 3 O₂

SnCl₄ + 6 Cl₂O₆ → [ClO₂]₂[Sn(ClO₄)₆] + 4 ClO₂ + 2 Cl₂

Nevertheless, it can also react as a source of the ClO₃ radical:

2 AsF₅ + Cl₂O₆ → 2 ClO₃AsF₅

References

1. ^ C. F. Goodeve, F. A. Todd (1933). "Chlorine Hexoxide and Chlorine Trioxide". Nature 132 (3335): 514–515. doi:10.1038/132514b0. 
2. ^ Lopez, Maria; Juan E. Sicre (1990). "Physicochemical properties of chlorine oxides. 1. Composition, ultraviolet spectrum, and kinetics of the thermolysis of gaseous dichlorine hexoxide". J. Phys. Chem. 94 (9): 3860–3863. doi:10.1021/j100372a094. 
3. ^ Mary Eagleson (1994). Concise encyclopedia chemistry. Walter de Gruyter. p. 215. ISBN 3110114518. http://books.google.com/?id=Owuv-c9L_IMC. 
4. ^ Cunin, Frédérique; Catherine Deudon, Frédéric Favier, Bernard Mula, Jean Louis Pascal (2002). "First anhydrous gold perchlorato complex: ClO₂Au(ClO₄)₄. Synthesis and molecular and crystal structure analysis". Inorganic Chemistry 41 (16): 4173–4178. doi:10.1021/ic020161z. PMID 12160405. 
5. ^ Harry Julius Emeléus, Alan George Sharpe (1963). Advances in Inorganic Chemistry and Radiochemistry. Academic Press. p. 65. ISBN 0120236052. http://books.google.com/?id=pRXIwIV-hB8C.