一氯化碘（分子式：ICl）是一种互卤化物，为一种红棕色的化合物，其熔点接近室温。因为碘与氯电负度的差异，一氯化碘的极性很高，可当作是I的来源。

制备一氯化碘的方式，是直接将两种卤素以1：1摩尔比化合：

当将氯气通过碘晶体时，即可看见一氯化碘的棕色蒸气形成，将之冷凝即可得深棕色的一氯化碘液体。过量的氯气会将一氯化碘转为三氯化碘，此为一可逆反应：

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. 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'.