Iodine monochloride

Template:Chembox header | Iodine monochloride
Iodine monochloride Iodine monochloride
Template:Chembox header | General
Systematic name	iodine(I) chloride
Other names	iodine chloride
Molecular formula	ICl
SMILES	ICl
Molar mass	162.35 g/mol
Appearance	red to brown liquid
CAS number	[7790-99-0]
Template:Chembox header | Properties
Density and phase	3.10 g/cm3
Solubility in water	hydrolysis
Other solvents	carbon disulfide acetic acid pyridine
Melting point	27°C (α-form)
Boiling point	97.4°C (370.6 K)
Template:Chembox header | Structure
Crystal structure	?
Dipole moment	? D
Template:Chembox header | Hazards
MSDS	External MSDS
Main hazards	corrosive
NFPA 704
R/S statement	R: ? S: ?
RTECS number	?
Template:Chembox header | Supplementary data page
Structure and properties	n, É√r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Template:Chembox header | Related compounds
Related interhalogen compounds	Chlorine monofluoride, bromine monochloride, iodine monobromide
Template:Chembox header | Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references

Iodine monochloride is the compound with the formula ICl. This red brown compound melts just near room temperature. Because of the difference in the electronegativity of iodine and chlorine, ICl is highly polar and behaves as a source of “I⁺.”

Preparation of iodine monochloride entails simply combining the halogens in a 1:1 molar ratio, according to this equation:

I₂ + Cl₂ → 2 ICl

When chlorine gas is passed through iodine crystals, one observes the brown vapor of iodine monochloride. Dark brown iodine monochloride liquid is collected. Excess chlorine converts iodine monochloride into iodine trichloride in a reversible reaction:

ICl + Cl₂ → ICl₃

Polymorphs

Polymorphy is the phenomenon where a solid exists in two or more different crystalline forms. ICl has two polymorphs, α-ICl which are black needles (red by transmitted light) with a melting point of 27.2 °C and β-ICl which are black platelets (red-brown by transmitted light) with a melting point 13.9 °C.

Uses

ICl is a useful reagent in organic synthesis. It is used as a source of electrophilic iodine to synthesise certain aromatic iodides. It also cleaves C-Si bonds.

ICl, will also add to the double bond in alkenes to give chloro-iodo alkanes.

RCH=CHR’ + ICl → RCH(I)-CH(Cl)R’

When such reactions are conducted in the presence of sodium azide, one obtains the iodo-azide, RCH(I)-CH(N₃)R’.

External links

• MSDS sheet