Symbol

Ir

Atomic Number

77

Atomic Mass

192.217

Family

Group 9 (Viiib) Transition Metal Platinum Group Pronunciation

i-RI-dee-um

Overview

Indium is in Group 9 (VIIIB) of the periodic table. The periodic table is a chart that shows how elements are related to one another. Indium is a transition metal that is also part of the platinum family.

The metals in the platinum family are also known as the noble metals. They have this name because they do not react well with other elements and compounds. They appear to be "too superior" to react with most other substances. In fact, iridium is the most corrosion-resistant metal known. It is not affected by high temperatures, acids, bases, or most other strong chemicals. That property makes it useful in making objects that are exposed to such materials.

Iridium may be a key element in the puzzle of dinosaur extinction. Scientists search for iridium in the...