I'o-dīne, n.

n. [Fr. iodine, iode, from Gr. iōdēs, violet-like, from īon, a violet, and eidos, form.] (Chem.) A grayish or bluish-black solid, of a metallic luster, somewhat resembling plumbago, obtained from the ashes of sea-weed, and usually occurring in scales or crystals.

Iodine is soft and brittle, fuses at 225° of Fahrenheit, and at 347° becomes a beautiful violet vapor, whence its name. It has an acrid odor and taste, and is poisonous, though uncertain in its action. It is an element, its chemical equivalent being 12.71, and in a solid state its density is 4.948. In its free state, the smallest quantity colors starch blue. It is used in medicine as a local irritant, and to increase the secretive functions. Used in excess, it gives rise to iodism.

Iodine scarlet, a pigment of a very vivid and beautiful color, consisting of the iodide of mercury.—Iodine yellow, a pigment of a bright yellow color, consisting of the iodide of lead.