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| Names | |||
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| IUPAC name Dichlorine hexoxide | |||
| Other names Chlorine trioxide; Chloryl perchlorate; Chlorine(V,VII) oxide | |||
| Identifiers | |||
3D model (JSmol) | |||
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| Properties | |||
| 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) | ||
| Reacts | |||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards | oxidizer | ||
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |||
Dichlorine hexoxide is thechemical compound with themolecular formulaCl2O6 orO2Cl−O−ClO3, which is correct for its gaseous state. However, in liquid or solid form, thischlorine oxide ionizes into the dark red ionic compound chloryl perchlorate or dioxochloronium(V) perchlorate[ClO2]+[ClO4]−, which may be thought of as the mixedanhydride ofchloric andperchloric acids. This compound is a notable perchlorating agent.[1]
It was originally reported to exist as the monomeric chlorine trioxideClO3 in gas phase,[2] but was later shown to remain an oxygen-bridged dimer after evaporation and until thermal decomposition intochlorine perchlorate,Cl2O4, and oxygen.[3] The compoundClO3 was then rediscovered.[4]
It is a dark red fuming liquid at room temperature that crystallizes as a red ionic compound, chloryl perchlorate,[ClO2]+[ClO4]−. The red color shows the presence ofchloryl 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).
Cl2O6 isdiamagnetic and is a very strong oxidizing agent. Although stable at room temperature, it explodes violently on contact with organic compounds[5] It is a strong dehydrating agent:
Many reactions involvingCl2O6 reflect its ionic structure,[ClO2]+[ClO4]−, including the following:[6]
It reacts withgold to produce thechloryl salt[ClO2]+[Au(ClO4)4]−:[7]
Several othertransition metal perchlorate complexes are prepared using dichlorine hexoxide.
Nevertheless, it can also react as a source of theClO3 radical:[citation needed]
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