Appearance and Characteristics
Harmful effects:
In small doses, iodine is slightly toxic and it is highly poisonous in large amounts. Elemental iodine is an irritant which can cause sores on the skin. Iodine vapor causes extreme eye irritation.
Characteristics:
Iodine is a bluish-black, lustrous solid. Although it is less reactive than the elements above it in group 17 (fluorine, chlorine and bromine) it still forms compounds with many other elements. Although iodine is a non-metal, it displays some metallic properties. When dissolved in chloroform, carbon tetrachloride or carbon disulfide, iodine yields purple colored solutions. It is barely soluble in water, giving a yellow solution.
Uses of Iodine
Iodine is important in medicine, in both radioactive and non-radioactive forms. Iodide and thyroxin, which contains iodine, are used inside the body. A solution containing potassium iodide (KI) and iodine in alcohol is used to disinfect external wounds. Elemental iodine is also used as a disinfectant. Silver iodide is used in photography. Iodine is sometimes added to table salt to prevent thyroid disease. Iodine’s other uses include catalysts, animal feeds and printing inks and dyes.