Indium is named after indigo, which is the color of the light released by its atoms when electrified. Its ores are rare, and most of the metal is obtained from lead and zinc ores, such as esphalerite. Pure indium is very soft, and is mainly used in compound form. For example, a compound called indium tin oxide is used in touch screens. Also, indium is used in microchips and to produce heat- and glare-resistant soldering goggles and masks.
Summary of properties (In)
| Atomic weight | 114.818(1) |
| Discoverer (year) | Reich, Ferdinand & Richter, Hieronymus (1863) |
| Natural form | metallic solid (tetragonal) |
| Electron configuration | [Kr] 4d10 5s2 5p1 |
| Melting point (ºC) | 157 |
| Boiling point (ºC) | 2000 |
| Abundance in earth's crust (ppm) | 0.25 |
| Isotope (abundance) | 113In (4.281), 115In (95.719) |
| Density g/cm3 | 7.31 |
| Van der Waals radius (pm) | 193 |
| Covalent radius (pm) | 142 |
| Electronegativity (Pauling) | 1.78 |
| Vaporization enthalpy (kJ/mol) | 226.40 |
| Enthalpy of fusion (kJ/mol) | 3.28 |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | 0.23 |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.820 |
| Oxidation state | +3 |
| Electron affinity (eV) | 0.30 |
| 1st Ionization potential (eV) | 5.7864 |
