Atomic Number: 49
Atomic Weight: 114.818
Discovery: Ferdinand Reich and T. Richter 1863 (Germany)
Electron Configuration: [Kr] 5s2 4d10 5p1
Word Origin: Latin indicum. Indium is named for the brilliant indigo line in the spectrum.
Isotopes: Twenty-three isotopes of indium are known. Only one stable isotope, In-127, occurs naturally.
Properties: The melting point of indium is 156.61 °C, boiling point is 2080 °C, specific gravity is 7.31 (20 °C), with a valence of 1, 2, or 3. Indium is a very soft, silvery-white metal. The metal has a brilliant luster and emits a high pitched sound when bent. Indium wets glass. Indium may be toxic, but further research is required to assess its effects.
Uses: Indium is used in low melting point alloys, making bearing alloys, transistors, thermistors, photoconductors, and rectifiers. When plated or evaporated onto glass, it forms a mirror as good as that formed by silver, but with superior resistance to atmospheric corrosion.
Sources: Indium often is associated with zinc materials. It is also found in iron, lead, and copper ores.
Element Classification: Metal
Density (g/cc): 7.31
Melting Point (K): 429.32
Boiling Point (K): 2353
Appearance: very soft, silvery-white metal
Atomic Radius (pm): 166
Atomic Volume (cc/mol): 15.7
Covalent Radius (pm): 144
Ionic Radius: 81 (+3e)
Specific Heat (@20°C J/g mol): 0.234
Fusion Heat (kJ/mol): 3.24
Evaporation Heat (kJ/mol): 225.1
Debye Temperature (K): 129.00
Pauling Negativity Number: 1.78
First Ionizing Energy (kJ/mol): 558.0
Oxidation States: 3
Lattice Structure: Tetragonal
Lattice Constant (Å): 4.590
References: Los Alamos National Laboratory (2001), Crescent Chemical Company (2001), Lange's Handbook of Chemistry (1952), CRC Handbook of Chemistry & Physics (18th Ed.)
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