Indium

Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust. Indium has a melting point higher than sodium and gallium, but lower than lithium and tin. Chemically, indium is similar to gallium and thallium, and it is largely intermediate between the two in terms of its properties.[8] Indium was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods. They named it for the indigo blue line in its spectrum. Indium was isolated the next year.

Quick facts: Indium, Pronunciation, Appearance, Standard a... ▼

Indium, ₄₉In

Indium
Pronunciation	/ˈɪndiəm/ ​(IN-dee-əm)
Appearance	silvery lustrous gray
Standard atomic weight Ar°(In)
	114.818±0.001 114.82±0.01 (abridged)[1]
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
Group	group 13 (boron group)
Period	period 5
Block	p-block
Electron configuration	[Kr] 4d10 5s2 5p1
Electrons per shell	2, 8, 18, 18, 3
Physical properties
Phase at STP	solid
Melting point	429.7485 K ​(156.5985 °C, ​313.8773 °F)
Boiling point	2345 K ​(2072 °C, ​3762 °F)
Density (near r.t.)	7.31 g/cm3
when liquid (at m.p.)	7.02 g/cm3
Triple point	429.7445 K, ​~1 kPa[2]
Heat of fusion	3.281 kJ/mol
Heat of vaporization	231.8 kJ/mol
Molar heat capacity	26.74 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,[3] +1, +2, +3[4] (an amphoteric oxide)
Electronegativity	Pauling scale: 1.78
Ionization energies	1st: 558.3 kJ/mol 2nd: 1820.7 kJ/mol 3rd: 2704 kJ/mol
Atomic radius	empirical: 167 pm
Covalent radius	142±5 pm
Van der Waals radius	193 pm
Spectral lines of indium
Other properties
Natural occurrence	primordial
Crystal structure	​body-centered tetragonal
Speed of sound thin rod	1215 m/s (at 20 °C)
Thermal expansion	32.1 µm/(m⋅K) (at 25 °C)
Thermal conductivity	81.8 W/(m⋅K)
Electrical resistivity	83.7 nΩ⋅m (at 20 °C)
Magnetic ordering	diamagnetic[5]
Molar magnetic susceptibility	−64.0×10−6 cm3/mol (298 K)[6]
Young's modulus	11 GPa
Mohs hardness	1.2
Brinell hardness	8.8–10.0 MPa
CAS Number	7440-74-6
History
Discovery	Ferdinand Reich and Hieronymous Theodor Richter (1863)
First isolation	Hieronymous Theodor Richter (1864)
Isotopes of indium v e
Main isotopes[7] 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
Category: Indium view talk edit | references

Indium is a minor component in zinc sulfide ores and is produced as a byproduct of zinc refinement. It is most notably used in the semiconductor industry, in low-melting-point metal alloys such as solders, in soft-metal high-vacuum seals, and in the production of transparent conductive coatings of indium tin oxide (ITO) on glass. Indium is considered a technology-critical element.

Indium has no biological role. Its compounds are toxic when injected into the bloodstream. Most occupational exposure is through ingestion, from which indium compounds are not absorbed well, and inhalation, from which they are moderately absorbed.