|Preferred IUPAC name
|Systematic IUPAC name
3D model (JSmol)
|Molar mass||162.35 g/mol|
|Melting point||27.2 °C (81.0 °F; 300.3 K) (α-form)
13.9 °C (β-form)
|Boiling point||97.4 °C (207.3 °F; 370.5 K)|
|Solubility||soluble in CS2
alcohol, ether, HCl
|Safety data sheet||External MSDS|
Related interhalogen compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Iodine monochloride is an interhalogen compound with the formula ICl. It is a red-brown chemical 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+.
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.
Reactions and uses
- ICl + H2O → HCl + HI + ½O2
The Wijs solution, iodine monochloride dissolved in acetic acid, is used to determine the iodine value of a substance.
It can also be used to make pure iodates, by reacting with a chlorate and releasing chlorine gas as byproduct.
- 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". Organic Syntheses. ; Collective Volume, 2, p. 349
- Padwa, A.; Blacklock, T.; Tremper, A. "3-Phenyl-2H-Azirine-2-carboxaldehyde". Organic Syntheses. ; Collective Volume, 6, p. 893