Germanium

  • germanium, 32ge
    grayish lustrous block with uneven cleaved surface
    germanium
    pronunciationm/ (may-nee-əm)
    appearancegrayish-white
    standard atomic weight ar, std(ge)72.630(8)[1]
    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
    galliumgermaniumarsenic
    atomic number (z)32
    groupgroup 14 (carbon group)
    periodperiod 4
    blockp-block
    element category  metalloid
    electron configuration[ar] 3d10 4s2 4p2
    electrons per shell2, 8, 18, 4
    physical properties
    phase at stpsolid
    melting point1211.40 k ​(938.25 °c, ​1720.85 °f)
    boiling point3106 k ​(2833 °c, ​5131 °f)
    density (near r.t.)5.323 g/cm3
    when liquid (at m.p.)5.60 g/cm3
    heat of fusion36.94 kj/mol
    heat of vaporization334 kj/mol
    molar heat capacity23.222 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−4 −3, −2, −1, 0,[2] +1, +2, +3, +4 (an amphoteric oxide)
    electronegativitypauling scale: 2.01
    ionization energies
    • 1st: 762 kj/mol
    • 2nd: 1537.5 kj/mol
    • 3rd: 3302.1 kj/mol
    atomic radiusempirical: 122 pm
    covalent radius122 pm
    van der waals radius211 pm
    color lines in a spectral range
    spectral lines of germanium
    other properties
    natural occurrenceprimordial
    crystal structureface-centered diamond-cubic
    diamond cubic crystal structure for germanium
    speed of sound thin rod5400 m/s (at 20 °c)
    thermal expansion6.0 µm/(m·k)
    thermal conductivity60.2 w/(m·k)
    electrical resistivity1 Ω·m (at 20 °c)
    band gap0.67 ev (at 300 k)
    magnetic orderingdiamagnetic[3]
    magnetic susceptibility−76.84·10−6 cm3/mol[4]
    young's modulus103 gpa[5]
    shear modulus41 gpa[5]
    bulk modulus75 gpa[5]
    poisson ratio0.26[5]
    mohs hardness6.0
    cas number7440-56-4
    history
    namingafter germany, homeland of the discoverer
    predictiondmitri mendeleev (1869)
    discoveryclemens winkler (1886)
    main isotopes of germanium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    68ge syn 270.95 d ε 68ga
    70ge 20.52% stable
    71ge syn 11.3 d ε 71ga
    72ge 27.45% stable
    73ge 7.76% stable
    74ge 36.7% stable
    76ge 7.75% 1.78×1021 y ββ 76se
    category category: germanium
    | references

    germanium is a chemical element with the symbol ge and atomic number 32. it is a lustrous, hard-brittle, grayish-white metalloid in the carbon group, chemically similar to its group neighbours silicon and tin. pure germanium is a semiconductor with an appearance similar to elemental silicon. like silicon, germanium naturally reacts and forms complexes with oxygen in nature.

    because it seldom appears in high concentration, germanium was discovered comparatively late in the history of chemistry. germanium ranks near fiftieth in relative 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. nearly two decades later, in 1886, clemens winkler found the new element along with silver and sulfur, in a rare mineral called argyrodite. although the new element somewhat resembled arsenic and antimony in appearance, the combining ratios in compounds agreed with mendeleev's predictions for a relative of silicon. winkler named the element after his country, germany. today, 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.

    germanium is not thought to be an essential element for any living organism. some complex organic germanium compounds are being investigated as possible pharmaceuticals, though none have yet proven successful. similar to silicon and aluminium, natural 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.

  • history
  • characteristics
  • production
  • applications
  • precautions for chemically reactive germanium compounds
  • see also
  • notes
  • references
  • external links

Germanium, 32Ge
Grayish lustrous block with uneven cleaved surface
Germanium
Pronunciationm/ (MAY-nee-əm)
Appearancegrayish-white
Standard atomic weight Ar, std(Ge)72.630(8)[1]
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
galliumgermaniumarsenic
Atomic number (Z)32
Groupgroup 14 (carbon group)
Periodperiod 4
Blockp-block
Element category  Metalloid
Electron configuration[Ar] 3d10 4s2 4p2
Electrons per shell2, 8, 18, 4
Physical properties
Phase at STPsolid
Melting point1211.40 K ​(938.25 °C, ​1720.85 °F)
Boiling point3106 K ​(2833 °C, ​5131 °F)
Density (near r.t.)5.323 g/cm3
when liquid (at m.p.)5.60 g/cm3
Heat of fusion36.94 kJ/mol
Heat of vaporization334 kJ/mol
Molar heat capacity23.222 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−4 −3, −2, −1, 0,[2] +1, +2, +3, +4 (an amphoteric oxide)
ElectronegativityPauling scale: 2.01
Ionization energies
  • 1st: 762 kJ/mol
  • 2nd: 1537.5 kJ/mol
  • 3rd: 3302.1 kJ/mol
Atomic radiusempirical: 122 pm
Covalent radius122 pm
Van der Waals radius211 pm
Color lines in a spectral range
Spectral lines of germanium
Other properties
Natural occurrenceprimordial
Crystal structureface-centered diamond-cubic
Diamond cubic crystal structure for germanium
Speed of sound thin rod5400 m/s (at 20 °C)
Thermal expansion6.0 µm/(m·K)
Thermal conductivity60.2 W/(m·K)
Electrical resistivity1 Ω·m (at 20 °C)
Band gap0.67 eV (at 300 K)
Magnetic orderingdiamagnetic[3]
Magnetic susceptibility−76.84·10−6 cm3/mol[4]
Young's modulus103 GPa[5]
Shear modulus41 GPa[5]
Bulk modulus75 GPa[5]
Poisson ratio0.26[5]
Mohs hardness6.0
CAS Number7440-56-4
History
Namingafter Germany, homeland of the discoverer
PredictionDmitri Mendeleev (1869)
DiscoveryClemens Winkler (1886)
Main isotopes of germanium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
68Ge syn 270.95 d ε 68Ga
70Ge 20.52% stable
71Ge syn 11.3 d ε 71Ga
72Ge 27.45% stable
73Ge 7.76% stable
74Ge 36.7% stable
76Ge 7.75% 1.78×1021 y ββ 76Se
Category Category: Germanium
| references

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard-brittle, grayish-white metalloid in the carbon group, chemically similar to its group neighbours silicon and tin. Pure germanium is a semiconductor with an appearance similar to elemental silicon. Like silicon, germanium naturally reacts and forms complexes with oxygen in nature.

Because it seldom appears in high concentration, germanium was discovered comparatively late in the history of chemistry. Germanium ranks near fiftieth in relative 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. Nearly two decades later, in 1886, Clemens Winkler found the new element along with silver and sulfur, in a rare mineral called argyrodite. Although the new element somewhat resembled arsenic and antimony in appearance, the combining ratios in compounds agreed with Mendeleev's predictions for a relative of silicon. Winkler named the element after his country, Germany. Today, 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.

Germanium is not thought to be an essential element for any living organism. Some complex organic germanium compounds are being investigated as possible pharmaceuticals, though none have yet proven successful. Similar to silicon and aluminium, natural 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.