Iodine

Symbol

I

Atomic number

53

Atomic mass	126.904		Thermal conductivity	0.00449
Atomic radius	1.32		Covalent radius	1.33
Density	4.92		Atomic volume	25.74
Melting point	386.7		Oxidation states	+/-1,5,7
Boiling point	458.4		Stable isotopes	1
Heat of vapor.	20.752		Electronegativity	2.66
Heat of fusion	7.824		First ionization	10.451
Specific heat	0.214		Electrical conduct.	...

Electron configuration

Iodine

Iodine in pure form is an almost black crystalline solid with a slightly metallic lustre. Warmed gently, it gives off a dense, beautiful blue-violet vapor of diatomic iodine. It exhibits a similar blue-violet color in solution in chloroform, carbon tetrachloride, and carbon disulfide, suggesting that it molecular form is maintained in such solutions.

Iodine occurs as iodide ion in very small quantities in sea water. In Chile saltpeter it occurs as a small amount of sodium iodate, NaIO3. Most of its commercial sources come from the saltpeter. Iodine can also be obtained from kelp, which concentrates it from sea water. The concentrated brines brought up from oil wells also provide a source.

Iodine in solution in alcohol is called tincture of iodine, and is used as a topical antiseptic. Its different color, reddish brown, indicates a form different from I2.

Hydrogen iodide, HI, is a colorless gas and its solution in water forms a strong acid, hydroiodic acid.

Iodine Nuclear Data