Germanium (Ge)
Element 32 · Metalloid · atomic mass 72.63 u · group 14, period 4
Electron shells: 2, 8, 18, 4
Germanium was the semiconductor of the first transistors before silicon displaced it. It has come back for fibre optics and infrared optics, where silicon cannot compete.
The very first transistor, built at Bell Labs in 1947, was germanium, not silicon.
- Atomic number
- 32
- Atomic mass
- 72.63 u
- Electron configuration
- [Ar] 4s² 3d¹⁰ 4p²
- Group · period · block
- 14 · 4 · p
- Oxidation states
- −4, +2, +4
- Electronegativity
- 2.01 (Pauling)
- Melting point
- 938 °C
- Boiling point
- 2,833 °C
- Density
- 5.323 g/cm³
- State at 20 °C
- Solid
- Appearance
- Greyish-white, brittle metalloid
- Discovered
- Clemens Winkler, 1886
32 protons, and 32 electrons when neutral
IUPAC standard atomic weight
Carbon group
What Germanium is used for
- Fibre-optic cable cores
- Infrared night-vision optics
- High-speed SiGe chips
- Polymerisation catalysts
Atomic structure of Germanium
A neutral germanium atom has 32 protons and 32 electrons. Its most common isotope carries about 41 neutrons, which is where the mass number 73 comes from. Change the neutron count and you have a different isotope of germanium; change the proton count and you have a different element entirely.
Those electrons fill shells from the inside out: 2, 8, 18, 4. In orbital notation that is [Ar] 4s² 3d¹⁰ 4p², leaving 4 valence electrons in the outer shell — the ones that do the chemistry.
3D electron orbitals
See where Germanium's electrons actually are — a cloud of 26,000 points sampled from the probability density |ψ|², not a cartoon of a lobe.
Where Germanium sits in the periodic table
Elements on the staircase between metals and non-metals, showing properties of both. Their intermediate conductivity is what makes semiconductors possible.
Discovery and naming
Germanium was discovered by Clemens Winkler in 1886. Its name comes from Latin Germania, "Germany".
Keep exploring
Atomic weight from IUPAC/CIAAW; physical properties from PubChem (US National Library of Medicine). Values that have never been measured are shown as “not measured” rather than estimated.
Related Calculators
Frequently Asked Questions
What is the atomic mass of Germanium?
The standard atomic weight of Germanium is 72.63 u, as published by IUPAC's Commission on Isotopic Abundances and Atomic Weights.
How many protons, neutrons and electrons does Germanium have?
Germanium has 32 protons, because the atomic number is the proton count and that is what makes an atom Germanium at all. A neutral Germanium atom has the same number of electrons, 32. The neutron count varies by isotope; the most common one has about 41, since 73 − 32 = 41.
What is the electron configuration of Germanium?
The electron configuration of Germanium is [Ar] 4s² 3d¹⁰ 4p². Its electrons are arranged 2, 8, 18, 4 across 4 shells.
Is Germanium a metal?
Not quite. Germanium is a metalloid — it sits on the staircase dividing metals from non-metals and shows properties of both, which is exactly why metalloids matter to the semiconductor industry.
What group and period is Germanium in?
Germanium is in group 14 (the carbon group), period 4, in the p-block. The group is its column and the period is its row.
What is the charge of Germanium?
Germanium most commonly forms a 4+ or 2+ ion. It has 4 outer electrons available to lose. Across all its compounds it shows oxidation states of −4, +2, +4.
What is the melting point of Germanium?
Germanium melts at 938 °C and boils at 2,833 °C. That puts it in the solids at everyday temperatures.
What is Germanium used for?
Fibre-optic cable cores, Infrared night-vision optics, High-speed SiGe chips, Polymerisation catalysts. Germanium was the semiconductor of the first transistors before silicon displaced it.
Who discovered Germanium, and where does its name come from?
Germanium (Ge) was discovered by Clemens Winkler in 1886. The name comes from Latin Germania, "Germany".