Iodine trichloride

Iodine trichloride is an interhalogen compound of iodine and chlorine. It is bright yellow but with time and upon exposure to light it turns red due to decomposition with formation of elemental iodine. In the solid state is present as a planar dimer I₂Cl₆, with two bridging Cl atoms.^[1]

Iodine trichloride

Full structural formula of the dimer
Space-filling model of the dimer
Commercial sample of iodine trichloride
Names
IUPAC name Iodine trichloride
Other names Diiodine hexachloride
Identifiers
CAS Number	865-44-1 Y
3D model (JSmol)	monomer: Interactive image dimer: Interactive image
ChemSpider	63265 Y
ECHA InfoCard	100.011.582
PubChem CID	70076
UNII	1E5KQ66TRQ Y
CompTox Dashboard (EPA)	DTXSID3061219
InChI InChI=1S/Cl3I/c1-4(2)3 Y Key: PAWIVBWALDNUJP-UHFFFAOYSA-N Y InChI=1/Cl3I/c1-4(2)3 Key: PAWIVBWALDNUJP-UHFFFAOYAF
SMILES monomer: ClI(Cl)Cl dimer: Cl[I-]1(Cl)[Cl+][I-]([Cl+]1)(Cl)Cl
Properties
Chemical formula	I2Cl6
Molar mass	466.5281 g/mol
Appearance	yellow solid
Density	3.11 g/cm3
Melting point	63 °C (145 °F; 336 K)
Magnetic susceptibility (χ)	−90.2×10−6 cm3/mol
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

It can be prepared by reacting iodine with an excess of liquid chlorine at −70 °C,^[2] or heating a mixture of liquid iodine and chlorine gas to 105 °C.^{[citation needed]} In the molten state it is conductive, which may indicate disproportionation into ions:^[2]

I₂Cl₆ ⇌ ICl⁺
₂ + ICl⁻
₄

It is an oxidizing agent, capable of causing fire on contact with organic materials.^{[citation needed]} That oxidizing power also makes it a useful catalyst for organic chlorination reactions.^[3]

Iodine trichloride reacts with concentrated hydrochloric acid, forming tetrachloroiodic acid:^[4]

ICl₃ + HCl → HICl₄