Germanium

Germanium, ₃₂Ge

Germanium
Pronunciation	/dʒɜːrˈmeɪniəm/ ​(jur-MAY-nee-əm)
Appearance	grayish-white
Standard atomic weight Ar°(Ge)
	72.630±0.008[1] 72.630±0.008 (abridged)[2]
Germanium 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 Si ↑ Ge ↓ Sn gallium ← germanium → arsenic
Atomic number (Z)	32
Group	group 14 (carbon group)
Period	period 4
Block	p-block
Electron configuration	[Ar] 3d10 4s2 4p2
Electrons per shell	2, 8, 18, 4
Physical properties
Phase at STP	solid
Melting point	1211.40 K ​(938.25 °C, ​1720.85 °F)
Boiling point	3106 K ​(2833 °C, ​5131 °F)
Density (at 20° C)	5.327 g/cm3[3]
when liquid (at m.p.)	5.60 g/cm3
Heat of fusion	36.94 kJ/mol
Heat of vaporization	334 kJ/mol
Molar heat capacity	23.222 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K) 1644 1814 2023 2287 2633 3104
Atomic properties
Oxidation states	common: −4, +2, +4 −3,? −2,? −1,? 0,[4] +1,[5] +3[5]
Electronegativity	Pauling scale: 2.01
Ionization energies	1st: 762 kJ/mol 2nd: 1537.5 kJ/mol 3rd: 3302.1 kJ/mol
Atomic radius	empirical: 122 pm
Covalent radius	122 pm
Van der Waals radius	211 pm
Spectral lines of germanium
Other properties
Natural occurrence	primordial
Crystal structure	​face-centered diamond-cubic (cF8)
Lattice constant	a = 565.774 pm (at 20 °C)[3]
Thermal expansion	5.79×10−6/K (at 20 °C)[3]
Thermal conductivity	60.2 W/(m⋅K)
Electrical resistivity	1 Ω⋅m (at 20 °C)
Band gap	0.67 eV (at 300 K)
Magnetic ordering	diamagnetic[6]
Molar magnetic susceptibility	−76.84×10−6 cm3/mol[7]
Young's modulus	103 GPa[8]
Shear modulus	41 GPa[8]
Bulk modulus	75 GPa[8]
Speed of sound thin rod	5400 m/s (at 20 °C)
Poisson ratio	0.26[8]
Mohs hardness	6.0
CAS Number	7440-56-4
History
Naming	after Germany, homeland of the discoverer
Prediction	Dmitri Mendeleev (1869)
Discovery	Clemens Winkler (1886)
Isotopes of germanium v e
Main isotopes[9] Decay abun­dance half-life (t1/2) mode pro­duct 68Ge synth 270.8 d ε 68Ga 70Ge 20.5% stable 71Ge synth 11.468 d ε 71Ga 72Ge 27.4% stable 73Ge 7.76% stable 74Ge 36.5% stable 76Ge 7.75% 1.78×1021 y β−β− 76Se
Category: Germanium view talk edit | references

Germanium is a chemical element; it has symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid (more rarely considered a metal) in the carbon group that is chemically similar to its group neighbors silicon and tin. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.

Because it seldom appears in high concentration, germanium was found comparatively late in the discovery of the elements. Germanium ranks 50th in abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev predicted its existence and some of its properties from its position on his periodic table, and called the element ekasilicon. On February 6, 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkler named the element after Germany, his country of birth. Germanium is mined primarily from sphalerite (the primary ore of zinc), though germanium is also recovered commercially from silver, lead, and copper ores.

Elemental germanium is used as a semiconductor in transistors and various other electronic devices. Historically, the first decade of semiconductor electronics was based entirely on germanium. Presently, the major end uses are fibre-optic systems, infrared optics, solar cell applications, and light-emitting diodes (LEDs). Germanium compounds are also used for polymerization catalysts and have most recently found use in the production of nanowires. This element forms a large number of organogermanium compounds, such as tetraethylgermanium, useful in organometallic chemistry. Germanium is considered a technology-critical element.^[10]

Germanium is not thought to be an essential element for any living organism. Similar to silicon and aluminium, naturally-occurring germanium compounds tend to be insoluble in water and thus have little oral toxicity. However, synthetic soluble germanium salts are nephrotoxic, and synthetic chemically reactive germanium compounds with halogens and hydrogen are irritants and toxins.