Dichlorine hexoxide is the chemical compound with the molecular formulaCl 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]
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] It is a strong dehydrating agent:
Cl2O6 + H2O → HClO4 + HClO3
Many reactions involving Cl2O6 reflect its ionic structure, [ClO 2]+ [ClO 4]− , including the following:[6]
^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.
