Carbon tetraiodide is slightly reactive towards water, giving iodoform and I. It is soluble in nonpolar organic solvents.  It decomposes thermally and photochemically to , CI.  Its synthesis entails AlCl-catalyzed halide exchange, which is conducted at room temperature:
The product crystallizes from the reaction solution.
Carbon tetraiodide is used as an iodination reagent, often upon reaction with bases. Ketones are converted to 1,1-diiodoalkenes upon treatment with triphenylphosphine (PPh) and carbon tetraiodide.  Alcohols are converted in and to iodide, by a mechanism similar to the Appel reaction. In an Appel reaction, carbon tetrachloride is used to generate alkyl chlorides from alcohols.