Element: Germanium

General data

Element name	Germanium
Chemical symbol	Ge
Atomic number Z	32
Year discovered	1886
Standard state (25°C)	Solid
Category	Metalloid
Block	p
Atomic mass	72.630
CPK color	#668F8F

Physical properties

Melting point	1211.4 K (938.3 °C)
Boiling point	3106 K (2833 °C)
Density	5.323 g/cm³

Energy properties

First ionization energy	7.9 eV
Electron affinity	1.35 eV

Atomic structure

Protons	32 (Atomic number)
Neutrons (Ge-74, most abundant isotope)	42
Electrons	32
Electron configuration	[Ar] 4s² 3d¹⁰ 4p²
Oxidation states	+4, +2
Electronegativity (Pauling)	2.01
Atomic radius (van der Waals)	211 pm

Ionization energies - NIST ASD (32 states)

State	Charge	Ioniz. energy (eV)	Type
Ge I	0+	7.899435 ± 0.000012	measured
Ge II	1+	15.93461 ± 0.000025	measured
Ge III	2+	34.0576 ± 0.0012	measured
Ge IV	3+	45.7155 ± 0.0012	measured
Ge V	4+	90.5 ± 0.019	measured
Ge VI	5+	115.9 ± 0.12	semi-empirical
Ge VII	6+	144.9 ± 1.5	calculated
Ge VIII	7+	176.4 ± 1.7	calculated
Ge IX	8+	212.5 ± 2.1	calculated
Ge X	9+	252.1 ± 2.2	calculated
Ge XI	10+	286 ± 3	calculated
Ge XII	11+	326 ± 2.5	calculated
Ge XIII	12+	367 ± 3	calculated
Ge XIV	13+	407 ± 3	calculated
Ge XV	14+	527.9 ± 1.6	semi-empirical
Ge XVI	15+	567.3 ± 0.5	semi-empirical
Ge XVII	16+	609.1 ± 0.8	semi-empirical
Ge XVIII	17+	662.8 ± 1.9	semi-empirical
Ge XIX	18+	706.7 ± 1	semi-empirical
Ge XX	19+	744 ± 3	semi-empirical
Ge XXI	20+	837.1 ± 1	semi-empirical
Ge XXII	21+	880.44 ± 0.03	semi-empirical
Ge XXIII	22+	2178.2 ± 0.4	measured
Ge XXIV	23+	2304 ± 4	semi-empirical
Ge XXV	24+	2439 ± 5	semi-empirical
Ge XXVI	25+	2575 ± 19	semi-empirical
Ge XXVII	26+	2737.1 ± 2.3	semi-empirical
Ge XXVIII	27+	2881.9 ± 1.6	semi-empirical
Ge XXIX	28+	3074 ± 3	semi-empirical
Ge XXX	29+	3194.293 ± 0.007	calculated
Ge XXXI	30+	13557.4218 ± 0.0019	calculated
Ge XXXII	31+	14119.4457 ± 0.0009	calculated

Value type as given by NIST ASD: measured - from evaluated experimental data; calculated - from ab initio calculations (mostly highly ionised atoms that have not been measured; for the simplest ones, e.g. H I, the calculation is more accurate than measurement); semi-empirical - from interpolation, extrapolation or another semi-empirical method.

Photos

Photo of the element: Germanium (Ge) — © images-of-elements.com (CC BY 3.0)

Isotopes (32)

A	N	Half-life	Decay
Ge-59	27	13.3 ms	EC/β⁺
Ge-60	28	25.0 ms	EC/β⁺
Ge-61	29	40.7 ms	EC/β⁺
Ge-62	30	73.5 ms	EC/β⁺
Ge-63	31	153.3 ms	EC/β⁺
Ge-64	32	64 s	EC/β⁺
Ge-65	33	30.8 s	EC/β⁺
Ge-66	34	2.26 h	EC/β⁺
Ge-67	35	18.9 min	EC/β⁺
Ge-68	36	271.04 d	EC
Ge-69	37	38.90 h	EC/β⁺
Ge-70	38	stable	-
Ge-71	39	11.42 d	EC
Ge-72	40	stable	-
Ge-73	41	stable	-
Ge-74	42	stable	-
Ge-75	43	82.78 min	β⁻
Ge-76	44	1.89×10²¹ a	2β⁻
Ge-77	45	11.211 h	β⁻
Ge-78	46	87 min	β⁻
Ge-79	47	18.97 s	β⁻
Ge-80	48	29.5 s	β⁻
Ge-81	49	6.4 s	β⁻
Ge-82	50	4.5 s	β⁻
Ge-83	51	1.85 s	β⁻
Ge-84	52	952 ms	β⁻
Ge-85	53	514 ms	β⁻
Ge-86	54	226 ms	β⁻
Ge-87	55	103 ms	β⁻
Ge-88	56	61 ms	β⁻
Ge-89	57	unknown	β⁻
Ge-90	58	unknown	β⁻

Data sources

PubChem Periodic Table API - Retrieved on 29 June 2026 - licence: CC0
IUPAC CIAAW - Abridged Standard Atomic Weights 2024 - Table version: 2024 - licence: Public domain
NNDC Wallet Cards 2023 - Data as of 15 October 2024 - licence: Public domain
Images of Elements - Retrieved on 29 June 2026 - licence: CC BY 3.0

More about the data sources