Dichlorine hexoxide

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Dichlorine hexoxide
Dichlorine hexoxide.svg
Identifiers
CAS number 12442-63-6 YesY
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
Hazards
Main hazards oxidizer
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Dichlorine hexoxide is the chemical compound with the molecular formula Cl
2
O
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.

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

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

Molecular structure[edit]

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]

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[edit]

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 [ClO
2
]+
[Au(ClO
4
)
4
]
.[4] Many other reactions involving Cl2O6 reflect its ionic structure, [ClO
2
]+
[ClO
4
]
, 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
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[edit]

  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 3-11-011451-8. 
  4. ^ Cunin, Frédérique; Catherine Deudon; Frédéric Favier; Bernard Mula; Jean Louis Pascal (2002). "First anhydrous gold perchlorato complex: ClO
    2
    Au(ClO
    4
    )
    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 0-12-023605-2.