Indium

Indium is a chemical element; it has symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are largely intermediate between the two. It was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods and named for the indigo blue line in its spectrum.

Not to be confused with Iridium.

Indium, 49In
Indium
Pronunciation/ˈɪndiəm/ ​(IN-dee-əm)
Appearancesilvery lustrous gray
Standard atomic weight Ar°(In)
Indium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
 Ga
↑
In
↓
Tl
cadmium ← indium → tin
Atomic number (Z)49
Groupgroup 13 (boron group)
Periodperiod 5
Block  p-block
Electron configuration[Kr] 4d10 5s2 5p1
Electrons per shell2, 8, 18, 18, 3
Physical properties
Phase at STPsolid
Melting point429.7485 K ​(156.5985 °C, ​313.8773 °F)
Boiling point2345 K ​(2072 °C, ​3762 °F)
Density (near r.t.)7.31 g/cm3
when liquid (at m.p.)7.02 g/cm3
Triple point429.7445 K, ​~1 kPa
Heat of fusion3.281 kJ/mol
Heat of vaporization231.8 kJ/mol
Molar heat capacity26.74 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1196 1325 1485 1690 1962 2340
Atomic properties
Oxidation states−5, −2, −1, 0, +1, +2, +3 (an amphoteric oxide)
ElectronegativityPauling scale: 1.78
Ionization energies
  • 1st: 558.3 kJ/mol
  • 2nd: 1820.7 kJ/mol
  • 3rd: 2704 kJ/mol
Atomic radiusempirical: 167 pm
Covalent radius142±5 pm
Van der Waals radius193 pm
Spectral lines of indium
Other properties
Natural occurrenceprimordial
Crystal structure ​body-centered tetragonal
Thermal expansion32.1 µm/(m⋅K) (at 25 °C)
Thermal conductivity81.8 W/(m⋅K)
Electrical resistivity83.7 nΩ⋅m (at 20 °C)
Magnetic orderingdiamagnetic
Molar magnetic susceptibility−64.0×10−6 cm3/mol (298 K)
Young's modulus11 GPa
Speed of sound thin rod1215 m/s (at 20 °C)
Mohs hardness1.2
Brinell hardness8.8–10.0 MPa
CAS Number7440-74-6
History
DiscoveryFerdinand Reich and Hieronymous Theodor Richter (1863)
First isolationHieronymous Theodor Richter (1864)
Isotopes of indium
Main isotopes Decay
abun­dance half-life (t1/2) mode pro­duct
111In synth 2.8 d ε 111Cd
113In 4.28% stable
115In 95.7% 4.41×1014 y β− 115Sn

Indium is a technology-critical element used primarily in the production of flat-panel displays as indium tin oxide (ITO), a transparent and conductive coating applied to glass. Indium is also used in the semiconductor industry, in low-melting-point metal alloys such as solders and soft-metal high-vacuum seals. It is produced exclusively as a by-product during the processing of the ores of other metals, chiefly from sphalerite and other zinc sulfide ores.

Indium has no biological role and its compounds are toxic when inhaled or injected into the bloodstream, although they are poorly absorbed following ingestion.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.