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Oxidation & Electrons | Appearance & Characteristics Reactions | Compounds | Radius | Conductivity Abundance & Isotopes 
Germanium (Photo: Gibe, GNU Free Documentation License) |
General:
| Name: Germanium | Symbol: Ge |
| Type: Non-Metal, 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 |
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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: 0.0003 x 10-6 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: $ 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%. | |
