Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid 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 discovered comparatively late in the discovery of the elements. 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. In 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkler named the element after his country, Germany. 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. 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.

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Atomic properties

Standard atomic weight72.63 ±0.008
Atomic mass72.6308 u

Atomic radii

Radius (empirical)122 pm
Radius (calculated)125 pm
Covalent radius122 pm
Van der Waals radius211 pm

Atomic shell

Electron configurationAr 3d10 4s2 4p2
Ionization energy(1st) 7.899435 eV
(2nd) 15.93461 eV
(3rd) 34.0576 eV
(4th) 45.7155 eV
(5th) 90.5001 eV
Shell model

Physical properties

Density5.323 g·cm−3 (293.1 K)
Molar volume1.363·10-5 m3·mol−1
Speed of sound5,400 m·s−1 (293.1 K)


Melting point1,211 K
Boiling point3,106 K
Liquid range1,894 K
Transition temperature5.4 K


Melting enthalpy31.8 kJ·mol-1
Enthalpy of vaporization334 kJ·mol-1
Binding energy377 kJ·mol-1

Heat and conductivity

Specific heat capacity308.3 J·kg−1·K−1
Thermal conductivity60 W·m-1·K-1
Expansion coefficient6·10-6 K-1
Work function5 eV


Mohs hardness6

Electrical properties

Electrical conductivity2 S·m-1
Resistance5·10-4 Ωm


Magnetic susceptibility-7.681·10-5 cm3·mol−1

Chemical properties

Oxidation state-4, 2, 4
Standard potential0.247 V (Ge2+ + 2e- → Ge)


Pauling scale2.01
Sanderson scale2.62
Allred-Rochow scale2.02
Mulliken scale2.33
Allen scale1.994
Ghosh-Gupta scale5.131 eV
Boyd-Edgecombe scale1.99
Nagle scale1.81
Pearson absolute negativity4.6 eV

Other properties

Natural occurrenceprimordial
Crystal structureDiamond structure
Goldschmidt Classificationchalcophile
Superconductorwith transition tempperature under special conditions
Price/kg962 ±48 USD

Natural abundances

200 ppb ≈ 2.01·1012 M☉
200 ppb ≈ 3.97·1011 Mt
21,000 ppb ≈ 20.9 g
Earth’s crust
1,400 ppb ≈ 38,700 Mt
0.06 ppb ≈ 82.2 kt