|Jmol-3D images||Image 1|
|Molar mass||162.35 g/mol|
|Appearance||red to brown liquid
97.4°C (370.6 K)
|Solubility in water||hydrolysis|
|Solubility||soluble in CS2
alcohol, ether, HCl
|Related interhalogen compounds||Chlorine monofluoride
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Iodine monochloride is an interhalogen compound with the formula ICl. It is a red-brown compound that melts 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+. Owing to the similarity of the properties of the compound with bromine (red-brown liquid at room temperature), its synthesis led early researchers to believe that the reaction between the heaviest and lightest of a 'triad' of elements (three elements with similar chemical properties, now found in the same group of the modern periodic table) would produce the central element of the triad, the so-named 'Law of Averages'.
Iodine monochloride is produced simply by combining the halogens in a 1:1 molar ratio, according to the 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
ICl has two polymorphs; α-ICl which exists as black needles (red by transmitted light) with a melting point of 27.2 °C, and β-ICl which exists as black platelets (red-brown by transmitted light) with a melting point 13.9 °C.
- RCH=CHR’ + ICl → RCH(I)-CH(Cl)R’
This solution, which is iodine monochloride dissolved in acetic acid, is used to determine the iodine value of a substance.
- Brisbois, R. G.; Wanke, R. A.; Stubbs, K. A.; Stick, R. V. "Iodine Monochloride" Encyclopedia of Reagents for Organic Synthesis, 2004 John Wiley & Sons. doi:10.1002/047084289X.ri014
- Carpenter, G. B.; Richards, S. M. (1 April 1962). "The crystal structure of β-iodine monochloride". Acta Crystallographica 15 (4): 360–364. doi:10.1107/S0365110X62000882.
- Wallingford, V. H.; Krüger, P. A. (1943), "5-Iodo-anthranilic Acid", Org. Synth.; Coll. Vol. 2: 349
- Padwa, A.; Blacklock, T.; Tremper, A., "3-Phenyl-2H-Azirine-2-carboxaldehyde", Org. Synth.; Coll. Vol. 6: 893