the mass of iodine (in grams) joined to 100 g of organic substance. The iodine number, which describes the double-bond content in an unsaturated compound, is determined during the study of fats and the analysis of fatty acids and the establishment of the content of admixtures that react with iodine in aromatic hydrocarbons. In certain cases, to determine the iodine number the mass of bromine, which combines more readily, is established, and the equivalent mass of iodine is then calculated.