Germanium: the essentials
Germanium is a gray-white semi-metal, and in its pure state is crystalline and brittle, retaining its lustre in air at room temperature. It is a very important semiconductor material. Zone-refining techniques have led to production of crystalline germanium for semiconductor use with an impurity of only one part in 10-10.
Certain germanium compounds have a low mammalian toxicity, but a clear activity against certain bacteria, which makes them of interest as chemotherapeutic agents.
Germanium: historical information
Germanium was an element whose existence was predicted by Mendeleev in 1871. He predicted that the then unknown element germanium should resemble silicon in its properties. He suggested therefore the name ekasilicon (symbol Es). His predictions for the properties of germanium are remarkably close to the reality. Germanium was discovered in a mineral called argyrodite by Clemens Alexander Winkler in 1886.
Germanium around us Read more »
Germanium has no biological role but is said to stimulate the metabolism.
Germanium is not found as the free element in nature. Germanium is found in germanite, argyrodite, and some zinc ores. It is also present in coal and its presence in coal insures reserves for many years.
|Location||ppb by weight||ppb by atoms||Links|
|Human||(no data) ppb by weight||(no data) atoms relative to C = 1000000|
Physical properties Read more »
Heat properties Read more »
- Melting point: 1211.4 [938.3 °C (1720.9 °F)] K
- Boiling point: 3093 [2820 °C (5108 °F)] K
- Enthalpy of fusion: |203| kJ mol-1
Crystal structure Read more »
The solid state structure of germanium is: ccp (cubic close-packed).
Germanium: orbital properties Read more »
Germanium atoms have 32 electrons and the shell structure is 18.104.22.168. The ground state electronic configuration of neutral Germanium is [Ar].3d10.4s2.4p2 and the term symbol of Germanium is 3P0.
- Pauling electronegativity: 2.01 (Pauling units)
- First ionisation energy: 762 kJ mol‑1
- Second ionisation energy: 1537.5 kJ mol‑1
Isolation: there is normally no need to make germanium in the laboratory as it is readily available commercially. Germanium is available through the treatment of germanium dioxide, GeO2, with carbon or hydrogen. The extraction of germanium from flue dust is complex because of the difficulty in separating it from zinc, which is also present.
GeO2 + 2C → Ge + 2CO
GeO2 + 2H2 → Ge + 2H2O
Very pure germanium can be made by the reaction of GeCl4 with hydrogen.
GeCl4 + 2H2 → Ge + 4HCl
Germanium isotopes Read more »
Germanium isotopes are mainly used for the production of medical As and Se radioisotopes. Ge-74 is used for the production of As-74, Ge-76 for the production of As-77, Ge-74 for the production of As-73 and Ge-72 for As-72. Ge-70, Ge-72 and Ge-74 can all be used for the production of the medical radioisotope Se-73, although the most common production route is via natural As (As-75). Natural GeF4 is used in the semiconductor pre-amorphisation implant process. The use of Ge-72, in the form of GeF4, improves this process and reduces contamination.
|70Ge||69.9242497 (16)||20.84 (87)||0|
|72Ge||71.9220789 (16)||27.54 (34)||0|
|73Ge||72.9234626 (16)||7.73 (5)||9/2||-0.8794669|
|74Ge||73.9211774 (15)||36.28 (73)||0|
|76Ge||75.9214016 (17)||7.61 (38)||0|