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Barium (Ba)
We are a leading manufacturer and supplier of research materials
Barium 56Ba137.327
Discovered in 1808 by Sir Humphry Davy at London, England.
[Greek: barys = heavy, Latin: barium]
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 fraom 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 glas.
Further Materials properties
| Crystal structure: |
(cell dimensions/pm), space group, b.c.c. (a=502.5), Im3m, high pressure form (a=390.1, c=615.5), P63/mmc |
|---|---|
| X-ray diffractions mass absorption coefficients: | CuKa 330 (µ/r) / cm2g-1 MoKa 43.5 (µ/r) / cm2g-1 |
| Neutron scattering length: | 0.507 b/10-12 cm |
| Thermal neutron capture cross-section: | 1.3 sa / barns |
| Density: | 3594 kg/m-3 [293 K] 3325 [liquid at m.p.] |
| Melting point: | 728.85 °C / 1002°K (α, under pressure) |
| Boiling point: | 1636.85 °C / 1910°K |
| Molar volume: | 38.21 cm3 |
| Thermal conductivity: | 18.4 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: | (18.1- 21.) x 10-6 K-1 |
| Electrical resistivity: | 50 x 10-8 [273 K] Ωm |
| Mass magnetic susceptibility: | +1.9 x 10-9 kg-1m3 |
| Young's modulus | 12.8 GPa |
| Rigidity modulus | 4.86 GPa |
| Bulk modulus | n.a. |
| Poisson's ratio | 0.28 GPa |
| Radi: | 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 |
| Isotope 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 ppm |
| Liver: | 0.04 - 1.2 ppm |
| Muscle: | 0.09 ppm |
| Daily dietary intake: | 0.6 - 1.7 mg |
| Total mass of element in average [70 kg] person: |
22 mg |
Geological data
| Minerals: | ||||
|---|---|---|---|---|
| Mineral | Formula | Density | Hardness | Crystal apperance |
| Barite | BaSO4 | 4.50 | 3 - 3.5 | orth., vitr./res. colourless-yellow |
| Benitoite (gemstone) | BaTiSi3O2 | 3.6 | 6.3 | hex., trans. blue |
| Witherite | BaCO3 | 4.219 | 3-3.5 | orth., vitr./res. colourless/grey |
| Chief ores: | barite mainly, witherite occasionally |
|---|---|
| World production: | 6 x 106 (barium ores) tonnes/year |
| 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 1012) |
| Earth's crust: | 500 ppm |
| Seawater | |
| Atlantic surface: | 4.7 x 10-3 ppm |
| Atlantic deep: | 9.3 x 10-3 ppm |
| Pacific surface: | 4.7 x 10-3 ppm |
| Pacific deep: | 20.0 x 10-3 ppm |
| Residence time: | 10 000 years |
| Classification: | recycled |
| Oxidation state: | II |
Source: Emsley, J. (1998) The Elements (3rd Edition)
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