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1807 von Sir Humphry Davy in London, UK, dargestellt.
[Lateinisch, natrium; Englisch, soda]
French: sodium
English: sodium
Italian: sodio
Spanish: sodio
Beschreibung: Weiches, silberweißes Metall. das an Schnittflächen schnell oxidiert. Reagiert heftig mit Wasser. Es wird in großen Mengen hergestellt und als Metall in Wärmetauschern von Kernreaktoren eingesetzt. NaCl ist ein Schlüsselprodukt für doe chemische Industrie, verwendet zur Herstellung von Cl2, NaOH usw.
Crystal structure: |
(cell dimensions/pm), space group, |
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X-ray diffractions mass absorption coefficients: | CuKa 30.1 (µ/r) / cm2g-1 MoKa 3.21 (µ/r) / cm2g-1 |
Neutron scattering length: | 0.358 b/10-12 cm |
Thermal neutron capture cross-section: | 0.530 sa / barns |
Density: | 971 kg/m-3 [293 K]; 928 [liquid at m.p.] |
Melting point: | 97.81°C / 370.96°K |
Boiling point: | 882.95°C / 1156.1°K |
Molar volume: | 23.68 cm3 |
Thermal conductivity: | 141 [300 K] W m-1K-1 |
Coefficient of linear thermal expansion: | 70.6 x 10-6 K-1 |
Electrical resistivity: | 4.2 x 10-8 [273 K] Ωm |
Mass magnetic susceptibility: | +8.8 x 10-9(s) kg-1m3 |
Radi: | Na+ 98; atomic 154; van der Waals 231 |
Electronegativity: | 0.93 (Pauling); 1.01 (Allred); 2.85 eV (absolute) |
Effective nuclear charge: | 2.20 (Slater); 2.51 (Clementi); 3.21 (Froese-Fischer) |
Number of Isotopes (incl. nuclear isomers): | 14 |
Isotope mass range: | 19-> 31 |
Biological role: | Essential to most species including humans. |
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Toxicity | |
Toxic intake: | chloride, oral, human = 12 g kg-1 |
Lethal intake: | LD50 (chloride, oral, rat) = 3000 mg kg-1 |
Hazards: | Sodium compounds are not hazardous insofar as their sodium content is concerned, but excess sodium chloride can be toxic by ingestion. A daily intake in excess of the necessary 2-3g is not advisable for those people suffering heart disease. |
Level in humans | |
Blood: | 1970 mg dm-3 |
Bone: | 10 000 ppm |
Liver: | 2000 - 4000 ppm |
Muscle: | 2600 - 7800 ppm |
Daily dietary intake: | 2 - 15 g |
Total mass of element in average [70 kg] person: |
100 g |
Minerals: | Sodium occurs in many minerals but these are not mined as a source of sodium. | |||
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Mineral | Formula | Density | Hardness | Crystal apperance |
Halite (rock salt) | NaCl | 2.168 | 2 | cub., vit. usually colourless |
Trona | Na3(CO3)(HCO3).2H2O | 2.14 | 2.5 - 3 | mon., vit. colourless |
Chief ores: | halite, trona |
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World production: | c. 200 000 (sodium metal); 168 x 106 (sodium carbonate) tonnes/year |
Main mining areas: | halite in Germany, Poland, USA, UK; trona in Kenya, USA |
Reserves: | almost unlimited |
Specimen: | available as ingots or lumps, in sealed ampoules under nitrogen, or spheres and stick stored under mineral oil. Warning! |
Abundances | |
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Sun: | 1.91 x 106 (relative to H = 1 x 1012) |
Earth's crust: | 23 000 ppm |
Seawater | 10 500 ppm |
Residence time: | 1 x 108 years |
Classification: | accumulating |
Oxidation state: | I |
Source: Emsley, J. (1998) The Elements (3rd Edition)
Other sizes and specifications on request