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Calcium (Ca)
We are a leading manufacturer and supplier of research materials
Calcium 20Ca40.078
Isolated in 1808 by Sir Humphry Davy at London, England.
[Latin, calx = lime]
French: calcium
German: Calzium
Italian: calcio
Spanish: calcio
Description: Calcium is a silvery-white, relatively soft metal that is obtained by heating calcium oxide (CaO) with aluminium metal in a vacuum. Although calcium metal is attacked by oxygen and water, the bulk metal is protected by an oxide-nitride film and can be worked as a metal. It is used in alloys and in the manufacture of zirconium, thorium, uranium and the rare earth metals. Calcium oxide (lime) is used in metallurgy, water treatment, chemicals industry, cement, etc.
Further Materials properties
| Crystal structure: | (cell dimensions/pm), space group, a-Ca f.c.c. (a=558.84), Fm3m β-Ca b.c.c. (a=448.0), Im3m γ-Ca h.c.p. (a=397, a=649), P62mmc [may contain H] T(a -> β) = 573 K; T (β -> γ) = 723 K |
|---|---|
| X-ray diffractions mass absorption coefficients: | CuKa 162 (µ/r) / cm2g-1 MoKa 18.3 (µ/r) / cm2g-1 |
| Neutron scattering length: | 0.476 b/10-12 cm |
| Thermal neutron capture cross-section: | 0.43 sa / barns |
| Density: | 1550.7 kg/m-3 [293 K]; 1365 [liquid at m.p.] |
| Melting point: | 838,85°C / 1112 °K |
| Boiling point: | 1483,85°C / 1757 °K (under pressure) |
| Molar volume: | 25.86 cm3 |
| Thermal conductivity: | 200 [300 K] W m-1K-1 |
| Coefficient of linear thermal expansion: | 22 x 10-6 K-1 |
| Electrical resistivity: | 3.43 x 10-8 [293 K] Ωm |
| Mass magnetic susceptibility: | +1.4 x 10-8(s) kg-1m3 |
| Young's modulus: | 19.6 GPa |
| Rigidity modulus: | 7.9 GPa |
| Bulk modulus: | 17.2GPa |
| Poisson's ratio: | 0.31 GPa |
| Radi: | Ca2+ 106; atomic 197 (a-form); covalent 174 |
| Electronegativity: | 1.00 (Pauling); 1.04 (Allred); 2.2 eV (absolute) |
| Effective nuclear charge: | 2.85 (Slater); 4.40 (Clementi); 5.69 (Froese-Fischer) |
| Number of Isotopes (incl. nuclear isomers): | 16 |
| Isotope mass range: | 36 -> 51 |
Biological data
| Biological role: | Essencial to all species |
|---|---|
| Toxicity | Non-toxic. |
| Toxic intake: | n.a. |
| Lethal intake: | LD50 (carbonate, oral, rat) = 6450 mg Kg-1 |
| Hazards: | Calcium compounds are only toxic via their other components |
| Level in humans | |
| Blood: | 60.5 mg dm-3 |
| Bone: | 170 000 ppm |
| Liver: | 100 - 360 ppm |
| Muscle: | 140 - 700 ppm |
| Daily dietary intake: | 600 - 1400 mg |
| Total mass of element in average [70 kg] person: |
1.00 kg |
Geological data
| Minerals: | Calcium occurs in many minerals. Below some main minerals. | |||
|---|---|---|---|---|
| Mineral | Formula | Density | Hardness | Crystal apperance |
| Anhydrate | CaSO4 | 2.98 | 3.5 | orth., vit./ pearly col. |
| Aragonite | CaCO2 | 2.947 | 3.5 - 4 | orth., vit. col.-white |
| Calcite | CaCO3 | 2.710 | 3 | orth. vit. col. (gem. onyx) |
| Dolomite | CaMg(CO3)2 | 2.85 | 3.4 - 4 | rhom., vit.col. |
| Chief ores: | calcite, dolomite, gypsum (used in cement and plaster) anhydrite (used to make H2SO4) |
|---|---|
| World production: | 2000 (calcium metal), 112 x 106 (lime, CaO) tonnes/year |
| Main mining areas: | comon everywhere |
| Reserves: | almost unlimited |
| Specimen: | available as granules, pieces or turnings. Care! |
| Abundances | |
|---|---|
| Sun: | 2.24 x 106 (relative to H = 1 x 1012) |
| Earth's crust: | 41 000 ppm |
| Seawater | |
| Altantic surface: | 390 ppm |
| Atlantic deep: | 430 ppm |
| Pacific surface: | 390 ppm |
| Pacific deep: | 440 ppm |
| Residence time: | 1 x 106 years |
| Classification: | recycled |
| Oxidation state: | II |
Source: Emsley, J. (1998) The Elements (3rd Edition)
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