Indium is a chemical element, having the chemical symbol In. Its atomic number (the number of protons) is 49. It has a standard atomic weight of 114.818 g•mol −1 and is a solid in its elemental form.
Indium is considered to be a member of the "Post-transition metal" class of elements. At a pressure of 101.325 kPa, it has a boiling point of 2,072 °C and a melting point of 156.6 °C.