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Barium 56Ba137.34
Discovered in 1808 by Sir Humphry Davy at London, England.
[Greek: barys=heavy ]
French: baryum
German: Barium
Italian: bario
Spanish: bario
Description: Barium is a soft silvery-white metal which oxidises in air and reacts with water. It is
obtained from barium oxide (BaO) by heating with aluminium. Barium sulfate is used commercially in drilling fluids for oil and gas exploration, and small
amounts of barium compounds are used in paints and glass.
Materials properties
| Density: |
3594 kg/m-3 [293 K]; 3325 [liquid at m.p.] |
| Melting point: |
1002 °K |
| Boiling point: |
1910 °K |
| Molar volume: |
38.21 cm3 |
| Thermal conductivity: |
18.4 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
(18.1 - 21.0) x 10-6 K-1 |
| Electrical resistivity: |
50 x 10-8 [273 K] Wm |
| Mass magnetic susceptibility: |
+1.9 x 10-9(s) kg-1m3 |
| Young's modulus: |
12.8 GPa |
| Rigidity modulus: |
4.86 GPa |
| Bulk modulus: |
n.a |
| Poisson's ratio: |
0.28 GPa |
| Radii: |
Ba2+143; atomic 217; covalent 198 |
| Electronegativity: |
0.89 (Pauling); 0.97 (Allred); 2.4 eV (absolute) |
| Effective nuclear charge: |
2.85 (Slater); 7.58 (Clementi); 10.27 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): |
37 |
| Issotope mass range: |
117 -> 148 |
Biological data
| Biological role: |
None, but barium is stimulatory. |
| Toxicity |
|
| Toxic intake: |
100 - 200 mg |
| Lethal intake: |
LD50(BaCO3, oral, rat) = 418 mg kg-1 |
| Hazards: |
Barium sulfate is insoluble and used for body imaging, but soluble barium salts are highly toxic causing vomiting, colic, diarrhoea, tremors, paralysis, etc.. |
| Level in humans |
|
| Blood: |
0.068 mg dm-3 |
| Bone: |
3 - 70 p.p.m. |
| Liver: |
0.04 - 1.2 p.p.m. |
| Muscle: |
0.09 p.p.m. |
| Daily dietary intake: |
0.6 - 1.7 mg |
| Total mass of element in average [70 kg] person: |
22 mg |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
b.c.c. (a=502.5), Im3m high pressure form: (a=390.1, c=615.5), P63/mmc |
| X-ray diffraction: mass absorption coefficients (µ/ρ) /cm2g-1: |
CuKα 330 MoKα 43.5 |
| Neutron scattering length, b/10-12cm: |
0.507 |
| Thermal neutron capture cross-section, σa/barns: |
1.3 |
Geological data
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Barite |
BaSo4 |
4.50 |
3 - 3.5 |
orth., vitr./res. colorless-yellow |
| Benitoite(gemstone) |
BaTiSi3O9 |
3.6 |
6.3 |
hex. trans. blue |
| Witherite |
BaCO3 |
4.219 |
3 - 3.5 |
orth., vitr./res. colorless/ gray |
| Chief ore: |
barite mainly, witherite occasionally |
| World production: |
6 x 106tonnes/year(barium ores) |
| Main mining areas: |
UK, Italy, Czech Republic (Pribram), USA, Germany |
| Reserves: |
450 x 106 tonnes |
| Specimen: |
available as granules, rods or stick. Warning! |
| Abundances |
|
| Sun: |
123 (relative to H = 1 x 1023) |
| Earth's crust: |
500 p.p.m. |
| Seawater: |
|
| Atlantic surface: |
4.7 x 10-3 p.p.m. |
| Atlantic deep: |
9.3 x 10-3 p.p.m. |
| Pacific surface: |
4.7 x 10-3 p.p.m. |
| Pacific deep: |
20.0 x 10-3 p.p.m. |
| Residence time: |
10 000 years |
| Classification: |
recycled |
| Oxidation state: |
II |
Other sizes and specifications on request
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