Germanium Element Facts

General States Energies Oxidation & Electrons Appearance & Characteristics Reactions Compounds Radius Conductivity Abundance & Isotopes

32 Ge 72.59 Germanium

Germanium (Photo: Gibe, GNU Free Documentation License)

General:

Name: Germanium	Symbol: Ge
Type: Metalloid, Carbon group	Atomic weight: 72.59
Density @ 293 K: 5.323 g/cm3	Atomic volume: 13.6 cm3/mol
Discovered: Germanium was discovered by Clemens A. Winkler in 1886. The element name comes from the Latin 'Germania', meaning Germany.

States

State (s, l, g): solid
Melting point: 1210.6 K   (938 oC)	Boiling point: 3103 K   (2830 oC)

Energies

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

Oxidation & Electrons

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

Appearance & Characteristics

Structure: diamond structure	Color: gray-white
Harmful effects: Germanium is not known to be toxic.	Hardness: 6 mohs
Germanium can harness solar energy much more efficiently than silicon.	Characteristics: 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. 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. Uses: 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.

Reactions

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

Compounds

Oxide(s): GeO, GeO2	Chloride(s): GeCl2, GeCl4
Hydride(s): GeH4, Ge2H6 + more

Radius

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

Conductivity

Thermal conductivity: 60.2 W m-1 K-1

Electrical conductivity: 3 S cm-1

Abundance & Isotopes

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

Source: 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.

Isotopes: 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%.