Dichlorine hexoxide

Names

IUPAC name

Dichlorine hexoxide

Other names

Chlorine trioxide; Chloryl perchlorate; Chlorine(V,VII) oxide

Identifiers

CAS Number

12442-63-6^Y

3D model (JSmol)

Interactive image
Interactive image

ChemSpider

9564507 incorrect charge

PubChem CID

101946322

InChI

InChI=1S/Cl2O6/c3-1(4)8-2(5,6)7
Key: BMVIIZAOKBSWDS-UHFFFAOYSA-N

SMILES

O=[Cl](=O)O[Cl](=O)(=O)=O
O=[Cl+]=O.[O-]Cl(=O)(=O)=O

Properties

Chemical formula

Cl₂O₆

Molar mass

166.901 g/mol

Appearance

red liquid

Density

1.65 g/cm³

Melting point

3.5 °C (38.3 °F; 276.6 K)

Boiling point

200 °C (392 °F; 473 K)

Solubility in water

Reacts

Hazards

Occupational safety and health (OHS/OSH):

Main hazards

oxidizer

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

Chemical compound

Dichlorine hexoxide is the chemical compound with the molecular formula Cl
₂O
₆, which is correct for its gaseous state. However, in liquid or solid form, this chlorine oxide ionizes into the dark red ionic compound chloryl perchlorate [ClO
₂]⁺
[ClO
₄]⁻
, which may be thought of as the mixed anhydride of chloric and perchloric acids. This compound is a notable perchlorating agent.^[1]

It is produced by reaction between chlorine dioxide and excess ozone:

2 ClO
₂ + 2 O
₃ → 2 ClO
₃ + 2 O
₂ → Cl
₂O
₆ + 2 O
₂

Molecular structure

It was originally reported to exist as the monomeric chlorine trioxide ClO₃ in gas phase,^[2] but was later shown to remain an oxygen-bridged dimer after evaporation and until thermal decomposition into chlorine perchlorate, Cl₂O₄, and oxygen.^[3] The compound ClO₃ was then rediscovered.^[4]

It is a dark red fuming liquid at room temperature that crystallizes as a red ionic compound, chloryl perchlorate, [ClO
₂]⁺
[ClO
₄]⁻
. The red color shows the presence of chloryl ions. Thus, chlorine's formal oxidation state in this compound remains a mixture of chlorine (V) and chlorine (VII) both in the gas phase and when condensed; however by breaking one oxygen-chlorine bond some electron density does shifts towards the chlorine (VII).

Properties

Cl₂O₆ is diamagnetic and is a very strong oxidizing agent. Although stable at room temperature, it explodes violently on contact with organic compounds^[5] and reacts with gold to produce the chloryl salt [ClO
₂]⁺
[Au(ClO
₄)
₄]⁻
.^[6] Many other reactions involving Cl₂O₆ reflect its ionic structure, [ClO
₂]⁺
[ClO
₄]⁻
, including the following:^[7]

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

2Au + 6Cl₂O₆ → 2[ClO
₂]⁺
[Au(ClO
₄)
₄]⁻
+ Cl₂

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

2 AsF₅ + Cl₂O₆ → 2 ClO₃AsF₅

References

^ Jean-Louis Pascal; Frédéric Favier (1998). "Inorganic perchlorato complexes". Coordination Chemistry Reviews. 178–180 (1): 865–902. doi:10.1016/S0010-8545(98)00102-7.
^ C. F. Goodeve, F. A. Todd (1933). "Chlorine Hexoxide and Chlorine Trioxide". Nature. 132 (3335): 514–515. Bibcode:1933Natur.132..514G. doi:10.1038/132514b0. S2CID 4116929.
^ 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.
^ Grothe, Hinrich; Willner, Helge (1994). "Chlorine Trioxide: Spectroscopic Properties, Molecular Structure, and Photochemical Behavior". Angew. Chem. Int. Ed. 33 (14): 1482–1484. doi:10.1002/anie.199414821.
^ Mary Eagleson (1994). Concise encyclopedia chemistry. Walter de Gruyter. p. 215. ISBN 3-11-011451-8.
^ Cunin, Frédérique; Catherine Deudon; Frédéric Favier; Bernard Mula; Jean Louis Pascal (2002). "First anhydrous gold perchlorato complex: ClO
₂Au(ClO
₄)
₄. Synthesis and molecular and crystal structure analysis". Inorganic Chemistry. 41 (16): 4173–4178. doi:10.1021/ic020161z. PMID 12160405.
^ Harry Julius Emeléus, Alan George Sharpe (1963). Advances in Inorganic Chemistry and Radiochemistry. Academic Press. p. 65. ISBN 0-12-023605-2.