I"o*dine (ī"?*dĭn or -dēn;
104), n. [Gr. 'iw`dhs violetlike;
'i`on a violet + e'i^dos form: cf. F.
iode, iodine. The name was given from the violet color
of its vapor. See Violet, Idyl.] (Chem.) A
nonmetallic element, of the halogen group, occurring always in
combination, as in the iodides. When isolated it is in the form of
dark gray metallic scales, resembling plumbago, soft but brittle, and
emitting a chlorinelike odor. Symbol I. Atomic weight 126.5. If
heated, iodine volatilizes in beautiful violet vapors.
☞ Iodine was formerly obtained from the ashes of seaweed
(kelp or varec), but is now also extracted from certain
natural brines. In the free state, iodine, even in very minute
quantities, colors starch blue. Iodine and its compounds are largely
used in medicine (as in liniments, antisyphilitics, etc.), in
photography, in the preparation of aniline dyes, and as an indicator
in titration.
Iodine green, an artificial green dyestuff,
consisting of an iodine derivative of rosaniline; -- called also
night green. -- Iodine scarlet, a
pigment of an intense scarlet color, consisting of mercuric
iodide. -- Iodine yellow, a brilliant
yellow pigment, consisting of plumbic iodide.