Atomic number:49

Group numbers:13

Period:5

Electronic configuration:[Kr] 4d¹⁰ 5s² 5p¹

Formal oxidation number:+3

Electronegativities:1.78

Atomic radius / pm:162.6

Relative atomic mass:114.818 ± 0.003

 

Indium was discovered by Ferdinand Reich and Hieronymus Theodor Richter (DE) in 1863. Named after the indicum (colour indigo), the colour it shows in a spectroscope. It is a rare, very soft, silver-white metal that is stable in air and water but dissolves in acids. Metal can ignite and burn. Indium is found in certain zinc ores. It is used to coat high speed bearings and as an alloy that lowers the melting point of other metals. Relatively small amounts are used in dental items and in electronic semiconductors.

Density / g dm^-3:7310 (298 K)

 7032 (m.p.)

Molar volume / cm³mol^-1:15.71 (298 K)

 16.33 (m.p.)

Electrical resistivity / μΩcm:8.37 (20 °C)

Thermal conductivity / W m^-1K^-1:81.6

Melting point / °C:156.6

Boiling point / °C:2072

Heat of fusion / kJ mol^-1:3.27

Heat of vaporization / kJ mol^-1:231.8

Heat of atomization / kJ mol^-1:243.72

1st ionization energy / kJ mol^-1:558.30

2nd ionization energy / kJ mol^-1:1820.67

3rd ionization energy / kJ mol^-1:2704.50

in the atmosphere / ppm:-

in the Earth's crust / ppm:0.05

in the oceans / ppm:0.02