[ahy-uh-dahyn, -din; in Chemistry also ahy-uh-deen] /ˈaɪ əˌdaɪn, -dɪn; in Chemistry also ˈaɪ əˌdin/
a nonmetallic halogen element occurring at ordinary temperatures as a grayish-black crystalline solid that sublimes to a dense violet vapor when heated: used in medicine as an antiseptic. Symbol: I; atomic weight: 126.904; atomic number: 53; specific gravity: (solid) 4.93 at 20°C.
a bluish-black element of the halogen group that sublimates into a violet irritating gas. Its compounds are used in medicine and photography and in dyes. The radioisotope iodine-131 (radioiodine), with a half-life of 8 days, is used in the diagnosis and treatment of thyroid disease. Symbol: I; atomic no: 53; atomic wt: 126.90447; valency: 1, 3, 5, or 7; relative density: 4.93; melting pt: 113.5°C; boiling pt: 184.35°C
1814, formed by English chemist Sir Humphrey Davy (1778-1829) from French iode “iodine,” coined 1812 by French chemist Joseph Louis Gay-Lussac from Greek ioeides “violet-colored,” from ion “the violet; dark blue flower,” + eidos “appearance” (see -oid). Davy added the chemical suffix -ine (2) to make it analogous with chlorine and fluorine. So called from the color of the vapor given off when the crystals are heated.
iodine i·o·dine (ī’ə-dīn’, -dĭn, -dēn’)
A shiny, grayish-black element of the halogen group. It is corrosive and poisonous and occurs in very small amounts in nature except for seaweed, in which it is abundant. Iodine compounds are used in medicine, antiseptics, and dyes. Atomic number 53; atomic weight 126.9045; melting point 113.5°C; boiling point 184.35°C; specific gravity (solid, at 20°C) 4.93; valence 1, 3, 5, 7. See Periodic Table.
iodine-123 n. A radioisotope of iodine with a pure gamma emission and a physical half-life of 13.1 hours, used for studies of thyroid metabolism.
iodine-125 n. A radioisotope of iodine with a half-life of 60 days that is used as a tracer in thyroid studies and as therapy in hyperthyroidism.
noun, Chemistry. 1. a radioactive isotope of iodine having a mass number 131 and a half-life of 8.6 days, used in the diagnosis and treatment of disorders of the thyroid gland. iodine-131 n. A radioisotope of iodine that emits beta and gamma rays, has a half-life of 8.05 days, and is used as a tracer […]
iodine-fast adj. Of or relating to hyperthyroidism unresponsive to iodine therapy.