MetalloidElement 32 · p-block

Germanium (Ge)

Germanium (Ge) is a metalloid with atomic number 32 and a standard atomic weight of 72.630. At room temperature it is a solid that melts at 938 °C and boils at 2,833 °C.

32GeGermanium72.630

Atomic number

protons

Atomic weight

72.630

CIAAW 2024

Melting point

938 °C

1,211.4 K

Boiling point

2,833 °C

3,106.15 K

Density

5.323 g/cm³

near room temperature

Electronegativity

2.01

Pauling scale

State at 25 °C

Solid

Discovered

1886

Germany

Germanium at a glance

Identity

Symbol	Ge
Atomic number (Z)	32
Atomic weight	72.630 ± 0.008 (CIAAW 2024)
Category	Metalloid
Group	14 — carbon group
Period	4
Block	p-block
CAS number	7440-56-4

Atomic properties

Electron configuration	[Ar] 3d¹⁰ 4s² 4p² Full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p²
Electrons per shell	2, 8, 18, 4
Oxidation states	-4, +2, +4 Less common: -3, -2, -1, 0, +1, +3
Electronegativity (Pauling)	2.01
First ionisation energy	7.899 eV (762.2 kJ/mol) 2nd: 15.935 eV · 3rd: 34.058 eV
Electron affinity	1.233 eV
Atomic radius (empirical)	125 pm
Covalent radius	121 pm
Van der Waals radius	211 pm

Physical properties

State at 25 °C	Solid
Melting point	938.3 °C · 1,720.9 °F · 1,211.4 K
Boiling point	2,833 °C · 5,131.4 °F · 3,106.15 K
Density	5.3234 g/cm³
Specific heat capacity	0.32 J/(g·K)
Thermal conductivity	60.2 W/(m·K)
Crystal structure	Diamond cubic

Isotopes & abundance

Natural occurrence	Primordial
Radioactive	No
Natural isotopes (abundance)	⁷⁴Ge 36.52%, ⁷²Ge 27.45%, ⁷⁰Ge 20.52%, ⁷³Ge 7.76%, ⁷⁶Ge 7.75% (radioactive)
Stable isotopes	5
Known isotopes	33
Abundance in Earth's crust	1.5 mg/kg
Abundance in seawater	0.00005 mg/L

Atomic weights: CIAAW Abridged Standard Atomic Weights 2024. Other properties: standard reference compilations, checked October 2026; predicted values are marked.

Germanium electron configuration

Germanium has 32 electrons. Written in short form, its ground-state configuration is [Ar] 3d¹⁰ 4s² 4p² — the electrons of the noble gas argon, plus 3d¹⁰ 4s² 4p².Written out in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p².

As a member of group 14 it has 4 valence electrons in its outer shell (shell 4), which largely decide its chemistry.

3d↑↓↑↓↑↓↑↓↑↓

4s↑↓

4p↑↑

Discovery and name

Discovered

1886 — Clemens Winkler · Germany.

Name

Latin Germania, Germany.

Known for

A semiconductor predicted by Mendeleev as 'eka-silicon'. Used in fibre optics, infrared optics and early transistors.

Isotopes of germanium

Naturally occurring germanium is a mix of 5 isotopes. Each has 32 protons; they differ in the number of neutrons:

Isotope	Protons	Neutrons	Natural abundance	Stability
⁷⁴Ge	32	42	36.52%	stable
⁷²Ge	32	40	27.45%	stable
⁷⁰Ge	32	38	20.52%	stable
⁷³Ge	32	41	7.76%	stable
⁷⁶Ge	32	44	7.75%	radioactive · half-life 1.88 × 10²¹ years

33 isotopes of germanium are known in our data set (half-lives as published in nuclear data tables).

Germanium compared with group 14

The other elements in group 14 (carbon group), from top to bottom of the table:

Element	Z	Atomic weight	Melting point	Boiling point	Density	Electronegativity
Carbon	6	12.011	—	3,642 °C	2.2 g/cm³	2.55
Silicon	14	28.085	1,414 °C	3,265 °C	2.33 g/cm³	1.9
Germanium	32	72.630	938 °C	2,833 °C	5.323 g/cm³	2.01
Tin	50	118.71	232 °C	2,586 °C	7.287 g/cm³	1.96
Lead	82	207.2	327 °C	1,749 °C	11.3 g/cm³	2.33
Flerovium	114	[290]	—	—	9.928 g/cm³ (pred.)	—

Frequently asked questions

6 answers

What is the atomic mass of germanium?

The standard atomic weight of germanium is 72.630 ± 0.008 (CIAAW 2024), so one mole weighs about 72.630 grams.

How many protons, neutrons and electrons does germanium have?

A neutral germanium atom has 32 protons and 32 electrons. Its most common isotope, germanium-74, has 42 neutrons.

What is the electron configuration of germanium?

[Ar] 3d¹⁰ 4s² 4p² (in full: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p²).

What are the melting and boiling points of germanium?

Germanium melts at 938.25 °C (1,720.9 °F) and boils at 2,833 °C (5,131.4 °F).

Is germanium a metal?

Germanium is a metalloid — it has properties between metals and nonmetals. It is in group 14, period 4, and is a solid at room temperature.

Who discovered germanium?

1886 — Clemens Winkler (Germany).