Germanium (Ge)
Metalloid
Germanium is a brittle grey metalloid that launched the semiconductor era: the first transistors were germanium. Today it serves in fibre optics, infrared lenses and night-vision systems.
Position on the periodic table
Atomic properties
| Atomic number | 32 |
|---|---|
| Atomic mass | 72.6308 amu |
| Electron configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2 |
| Noble gas shorthand | [Ar] 3d10 4s2 4p2 |
| Electrons per shell | 2, 8, 18, 4 |
| Valence electrons (outer shell) | 4 |
| Common oxidation states | +4, +2 |
| Electronegativity (Pauling) | 2.01 |
| Covalent radius (approx.) | 120 pm |
| First ionization energy | 762 kJ/mol |
| Electron affinity | 118.9 kJ/mol |
Physical properties
| State at 25 °C | Solid |
|---|---|
| Density | 5.323 g/cm³ |
| Melting point | 938.25 °C (1211.4 K) |
| Boiling point | 2832.8 °C (3106 K) |
| Appearance | grayish-white |
| Radioactive | No |
| Origin | Occurs naturally |
Electron configuration of germanium
Germanium's ground-state electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2, usually shortened to [Ar] 3d10 4s2 4p2. Its electrons occupy 4 shells (2, 8, 18, 4), placing it in period 4 of the p-block. The 4 outer-shell electrons drive its bonding behaviour. Explore it interactively in the electron configuration calculator.
Uses of germanium
- Fibre-optic cores
- Infrared optics and night-vision lenses
- Polymerisation catalysts for PET plastic
- Specialty semiconductors and solar cells
Biological role: None known.
Occurrence: Dispersed in zinc ores and coal; recovered as a refining by-product.
Common compounds of germanium
GeO2
Germanium dioxide
GeCl4
Germanium tetrachloride
History and discovery
Discovered: 1886 — Clemens Winkler. Name origin: From Germania, Latin for Germany, homeland of its discoverer.
Clemens Winkler discovered it in 1886, matching Mendeleev's predicted “ekasilicon” almost exactly.
Safety notes
Low toxicity in normal handling; some germanium compounds are harmful if ingested.
Educational context only — always follow your school's laboratory rules and never handle chemicals without proper supervision. See our disclaimer.
Practice questions
Quick practice: Germanium
1. What is the chemical symbol of Germanium?
2. What is the atomic number of Germanium?
3. Which category does Germanium belong to?
4. What is the state of Germanium at room temperature?
5. Which period of the periodic table is Germanium in?
Germanium FAQs
What is the atomic number of germanium?
Germanium's atomic number is 32 — every germanium atom has 32 protons in its nucleus.
What is the symbol for germanium?
Ge. From Germania, Latin for Germany, homeland of its discoverer.
Is germanium a metal, nonmetal, or metalloid?
Germanium is classified as a metalloid — an element with properties between metals and nonmetals.
What state is germanium at room temperature?
At about 25 °C, germanium is a solid. It melts at 938.25 °C.
How many valence electrons does germanium have?
Germanium has 4 electrons in its outer shell (shell pattern: 2, 8, 18, 4).
What is germanium used for?
Key uses include: fibre-optic cores; infrared optics and night-vision lenses; polymerisation catalysts for pet plastic.
Related elements
Keep working with this element
Spotted an error? Report a correction · Data sources