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Gallium 31Ga69.72
Discovered in 1875 by Paul-Émile Lecoq de Boisbaudran at Paris, France.
[Latin: Gallia = France]
French: gallium
German: Gallium
Italian: gallio
Spanish: galio
Description: Gallium is a
soft, silvery-white metal, and has the longest liquid range of all the
elements. It is stable in air and with water; it dissolves in acids and alkalis.
Gallium has semiconductor properties, especially as gallium arsenide. It is used
in light-emitting diodes and microwave equipment.
Materials properties
| Density: |
5907 kg/m-3 [293 K]; 6113.6 [liquid at m.p.] |
| Melting point: |
302.93 °K |
| Boiling point: |
2676 °K |
| Molar volume: |
11.81 cm3 |
| Thermal conductivity: |
40.6 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
11.5 x 10-6 K-1 (a axis); 31.5 x 10-6 (b axis); 16.5 x 10-6 (c axis) |
| Electrical resistivity: |
2.7 x 10-8 [273 K] Wm varies with axis |
| Mass magnetic susceptibility: |
-3.9 x 10-8(s) kg-1m3 |
| Young's modulus: |
9.81 GPa |
| Rigidity modulus: |
6.67 GPa |
| Bulk modulus: |
n.a. |
| Poisson's ratio: |
0.47 GPa |
| Radii: |
Ga3+ 62; Ga+113; atomic 122; covalent 125 |
| Electronegativity: |
1.81 (Pauling); 1.82 (Allred); 3.2 eV (absolute) |
| Effective nuclear charge: |
5.00 (Slater); 6.22 (Clementi); 6.72 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
23 |
| Issotope mass range: |
62 -> 83 |
Biological data
| Biological role: |
None, but acts to stimulate metabolism. |
| Toxicity |
|
| Toxic intake: |
< 15mg k-1 tolerated without apparent harm |
| Lethal intake: |
LD50(chloride, injection, rat) = 47 mg kg-1 |
| Hazards: |
Gallium salts generally have low toxicity. |
| Level in humans |
|
| Blood: |
< 0.08 mg dm-3 |
| Bone: |
n.a. |
| Liver: |
0.025 p.p.m. |
| Muscle: |
0.0014 p.p.m. |
| Daily dietary intake : |
n.a. but low |
| Total mass of element in average [70 kg] person: |
< 0.7 mg |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
α-Ga orthorhombic (a = 451.86, b=765.70, c= 452.58), Cmca β-Ga orthorhombic (a=290, b=813, c=317), Cmcm (metastable form) γ-Ga orthorhombic (a=1060, b=1356, c=519), Cmc21 T(γ->α)= 238 K High pressure form: (a=279, c=438), I4/mmm |
| X-ray diffraction: mass absorption coefficients (µ/ρ)/cm2g-1: |
CuKα 67.9 MoKα 60.1 |
| Neutron scattering length, b/10-12cm: |
0.7288 |
| Thermal neutron capture cross-section, σa/barns : |
2.9 |
Geological data
| Minerals: |
Gallium minerals are rare, but gallium occurs in other ores to the extent of 1%. |
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Gallite |
CuGaS2 |
4.40 (calc.) |
3 - 3.5 |
tet., met. grey |
The ores diaspore, sphalerite, germanite and bauxite contain traces of gallium. Coal can also have a high gallium content.
| Chief ore: |
gallium is recovered as a by-product of zinc and copper refining. |
| World production: |
30 tonnes/year |
| Main mining areas: |
see copper and zinc. |
| Reserves: |
n.a. |
| Specimen: |
available as ingot, and as ultrapure gallium. Safe. |
| Abundances |
|
| Sun: |
631 (relative to H = 1 x 1023) |
| Earth's crust: |
18 p.p.m. |
| Seawater: |
3 x 10-5p.p.m. |
| Residence time: |
10 000 years |
| Classification: |
n.a. |
| Oxidation state: |
III |
Other sizes and specifications on request
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