Iodine is a nonmetallic, nearly black solid at room temperature and has a glittering crystalline appearance. The molecular lattice contains discrete diatomic molecules, which are also present in the molten and the gaseous states. Above 700 °C (1,300 °F), dissociation into iodine atoms becomes appreciable.

Why is iodine a metal?

Iodine is a metalloid. Metalloid elements have one or more allotropes with properties intermediate between those of a metal and a nonmetal. Metals are lustrous, ductile, and conductive of heat and electricity.

What family is iodine in?

Group 7A (or VIIA) of the periodic table are the halogens: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The name "halogen" means "salt former", derived from the Greek words halo- ("salt") and -gen ("formation").