Iodine monochloride is a chemical compound with the formula ICl. 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 a low melting black or brownish-red solid and widely available (usually in 97-98% purity). It is soluble in alcohol, ether, CS2, acetic acid, acetone and pyridine and hydrolyzes in water to HCl and IOH. ICl explodes on contact with potassium metal, mixes with sodium metal, and it can explode if impacted. Its reaction with PCl3 is extremely exothermic. [ ¹ ] Iodine monochloride can be easily prepared by adding an aqueous solution of potassium iodate to potassium iodate dissolved in concentrated HCl, in a closed vessel to avoid the loss of chlorine. [ ² ] Iodine monochloride is a versatile reagent for the synthesis of a large number of organic compounds being employed, for example, as a source of electrophilic iodine in the synthesis of certain aromatic iodides. [ ³ ] It cleaves C-Si bonds [ 4 ] and can be used in the electrophilic addition to the double bond in alkenes leading to chloroiodoalkanes. [ 5 ] When iodine monochloride is reacted with sodium azide in situ, the iodoazide product is obtained. [ 6 ] Other examples of synthetic applications of this reagent also include electrophilic substitutions in Csp [ ² ] and electrophilic cyclizations. [ 7-9 ]