|Type:Metalloid, Carbon group||Atomic weight:72.59|
|Density @ 293 K:5.323 g/cm3||Atomic volume:13.6 cm3/mol|
Germanium was discovered by Clemens A. Winkler in 1886. The element name comes from the Latin 'Germania', meaning Germany.
|State (s, l, g):solid|
|Melting point:1210.6 K (938 °C)||Boiling point:3103 K (2830 °C)|
|Specific heat capacity:0.32 J g-1 K-1||Heat of atomization:377 kJ mol-1|
|Heat of fusion:36.940 kJ mol-1||Heat of vaporization :334.3 kJ mol-1|
|1st ionization energy:762.1 kJ mol-1||2nd ionization energy:1537.4 kJ mol-1|
|3rd ionization energy:3301.7 kJ mol-1||Electron affinity:120 kJ mol-1|
|Shells:2,8,18,4||Electron configuration:[Ar] 3d10 4s2 4p2|
|Minimum oxidation number: -4||Maximum oxidation number:4|
|Min. common oxidation no.: -4||Max. common oxidation no.:4|
|Electronegativity (Pauling Scale):2.01||Polarizability volume:6.1 Å3|
Germanium is not known to be toxic.
Germanium is a lustrous, hard, gray-white semi-metallic element with a crystalline and brittle structure. Germanium also has the unusual property that (like water) it expands as it freezes. Four other elements expand when they freeze; silicon, bismuth, antimony and gallium. It is a semiconductor. Germanium and the oxide are transparent to infrared radiation.
The most common use of germanium is as a semiconductor. Germanium is used in transistors and in integrated circuits. It is used as an alloying agent and as a catalyst. It is also used in infrared spectroscopes and infrared detectors. Some germanium compounds are useful because they are toxic to bacteria but are harmless for mammals.
|Reaction with air: mild, w/ht ⇒ GeO2||Reaction with 6 M HCl:none|
|Reaction with 15 M HNO3:mild,⇒ Geiv, Nox||Reaction with 6 M NaOH:none|
|Oxide(s):GeO, GeO2||Chloride(s):GeCl2, GeCl4|
|Hydride(s):GeH4, Ge2H6 + more|
|Atomic radius:122.3 pm||Ionic radius (1+ ion): pm|
|Ionic radius (2+ ion):87 pm||Ionic radius (3+ ion): pm|
|Ionic radius (2- ion): pm||Ionic radius (1- ion): pm|
|Thermal conductivity:60.2 W m-1 K-1||Electrical conductivity:3 S cm-1|
|Abundance earth's crust:1.5 parts per million by weight, 0.42 parts per million by moles|
|Abundance solar system:200 parts per billion by weight, 3 parts per billion by moles|
|Cost, pure:$360 per100g|
|Cost, bulk:$120 per 100g|
The main ore of germanium is germanite, which is about 7% germanium. Commercially, germanium is obtained as a byproduct of metal refining and from some coal ashes.
Germanium has 24 isotopes whose half-lives are known, with mass numbers 58 to 85. Of these, five are stable: 70Ge, 72Ge 73Ge, 74Ge and 76Ge. The most abundant is 74Ge at 35.9%.