Germanium is a brittle semiconductor with a history in transistors and continuing uses in optical materials. Germanium and its oxide transmit infrared radiation, while the oxide also modifies optical glass. Its story connects the control of electric current with the passage of light through matter.
FROM ELEMENT TO APPLICATION
AN ELEMENT IN CONTEXT
How did germanium become an amplifying device rather than simply a semiconductor sample?
Purified and doped elemental germanium
FOLLOW THIS RELATIONSHIP
Prepare a controlled material
An early germanium transistor required semiconductor material with controlled electrical characteristics, making material preparation part of the device rather than a background detail.
Explore the model (optional)
GeFORM → INTERACTION → CONSEQUENCE
Follow the explanation in either direction. These are authored steps, not a physical clock.
Optional: check your understanding
USE THE EXPLANATION
What turns germanium into an amplifier?
Atomic identity, reference properties and structure models
INTERACTIVE 3D32 visible sites
An electron censusDrag to rotate · scroll or pinch to zoom
[Ar] 3d10 4s2 4p2. Grouping electrons by principal shell connects the neutral-atom configuration to periodic-table patterns.
What this representation means
A three-dimensional counting diagram. Dots are count markers, not measured electron positions; spherical placement and spacing are arbitrary. There are no electron trajectories here. Orbitals describe quantum states.
An unusual silver-bearing reached Clemens Winkler for analysis after its recognition in 1885. Most of its composition could be assigned to silver and sulfur, but a remaining fraction resisted explanation. In 1886 Winkler identified germanium, whose properties matched the missing element below silicon anticipated by Mendeleev. The discovery connected a local mineral specimen with an international test of the periodic arrangement.
1885
Unusual mineral investigated
A specimen from the Himmelsfürst mine prompted mineralogical and chemical analysis.
1886
Germanium identified
Winkler recognized the previously unexplained constituent as a new element.
Germanium occurs in minerals such as argyrodite and germanite and can accompany zinc and certain coals. Its recovery may therefore connect to processing another resource. Obtaining semiconductor-quality material adds a further challenge: the element must be separated and purified far beyond merely recognizing it in a mineral.
Germanium is a , crystalline metalloid and a . Deliberate additions of selected elements change its electrical behavior. The element and its also transmit infrared radiation over useful regions, showing that an optical material's behavior can differ substantially from how it looks under visible light.
Each section links its supporting references. Descriptions and diagrams were authored for this atlas. Source checks completed. Source checks dated 2026-09-06.
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Family labels and the group-3 layout are teaching conventions. A table position does not establish an unknown bulk property. Electronic configurations refer to neutral atoms; ions and material environments require their own account.
Read each reference property together with its units, conditions and the reference information below.
Not yet recorded: electron affinity, second ionization energy, ground-state term symbol, van der waals radius, thermal conductivity, specific heat capacity, electrical resistivity, crystal structure, lattice parameter a, space group, abundance in seawater, abundance in the universe, annual production, supply-risk listing, hazard classification, biological role, cas registry number, pubchem cid, wikidata item. These families are declared and awaiting an ingestion run against the source each names; they are listed here rather than shown as empty rows.
Physical
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Phase at 20 °C
solid
293.15 K, 101.325 kPa
Melting point in K
1211 K
at standard pressure unless noted
Boiling point in K
3106 K
101.325 kPa
Density in g/cm³
5.32 g/cm³
solids and liquids at 293 K; gases at 273 K and 101.325 kPa
Atomic and electronic
Intended reference: Pauling electronegativity scale · Widely tabulated; original in The Nature of the Chemical Bond
Electronegativity in Pauling
2.01 Pauling
Pauling scale
First ionization energy in kJ/mol
762 kJ/mol
gas-phase neutral atom, ground state
Covalent radius in pm
120 pm
single-bond covalent radius
Common oxidation states
+2, +4
states met in ordinary compounds; not exhaustive
Occurrence and identity
Intended reference: CRC Handbook of Chemistry and Physics · CRC Press
Abundance in the crust in mg/kg
1.5 mg/kg
upper continental crust, mass fraction
Has stable isotopes
Yesderived
Discovery year in CE
1886 CEderived
WHERE IT SITS AMONG ITS NEIGHBORS
Electronegativity across period 4
Ge 2.01 Pauling · Germanium
Electronegativity across period 4. Exact values.
K
0.82
Ca
1
Sc
1.36
Ti
1.54
V
1.63
Cr
1.66
Mn
1.55
Fe
1.83
Co
1.88
Ni
1.91
Cu
1.9
Zn
1.65
Ga
1.81
Ge
2.01
As
2.18
Se
2.55
Br
2.96
Kr
3
Electronegativity down group 14
Ge 2.01 Pauling · Germanium
Electronegativity down group 14. Exact values.
C
2.55
Si
1.9
Ge
2.01
Sn
1.96
Pb
2.33
The trend uses the same reference-property values as the periodic table. Elements with no recorded value are left out of the line rather than drawn at zero.
