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Sodium 11Na22.9898
Isolated by Sir Humphry Davy in 1807 at the Royal Institution, London, England.
[English: soda; Latin: natrium]
French: sodium
German: Natrium
Italian: sodio
Spanish: sodio
Description: Sodium is a soft,
silvery-white, metal which oxidises rapidly when cut, and reacts vigorously
with water. It is produced in large quantities by the electrolysis of molten
sodium chloride. Sodium metal is used in industry in the manufacture of other
chemicals and metals. It is also used in heat exchangers for nuclear reactors.
Materials properties
| Density: |
971 kg/m-3 [293 K]; 928 [liquid at m.p.] |
| Melting point: |
370.96 °K |
| Boiling point: |
1156.1 °K |
| Molar volume: |
23.68 cm3 |
| Thermal conductivity: |
141 [300 K] Wm-1K-1 |
| Coefficient of linear thermal expansion: |
70.6 x 10-6 K-1 |
| Electrical resistivity: |
4.2 x 10-8 [273 K] Wm |
| Mass magnetic susceptibility: |
+8.8 x 10-9(s) kg-1m3 |
| Young's modulus: |
6.80 GPa |
| Rigidity modulus: |
2.53 GPa |
| Bulk modulus: |
n.a. |
| Poisson's ratio: |
0.34 GPa |
| Radii: |
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 |
| Issotope mass range: |
19 -> 31 |
Biological data
| Biological role: |
Essential to most species including humans. |
| Toxicity |
|
| Toxic intake: |
chloride,oral,human = 12 g kg-1 |
| Lethal intake: |
LD 50 (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 2-3 g is not advisable for those people suffering heart disease.
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| Level in humans |
|
| Blood: |
1970 mg dm-3 |
| Bone: |
10 000 p.p.m. |
| Liver: |
2000 - 4000 p.p.m. |
| Muscle: |
2600 - 7800 p.p.m. |
| Daily dietary intake : |
2 - 15 mg |
| Total mass of element in average [70 kg] person: |
100 g |
Crystal data
| Crystal structure, (cell dimentions / pm), space group |
α-Na hexagonal (a = 376.7, c=615.4),P63/mmc β-Na b.c.c (a=429.06), Im3m T(b.c.c.->hexagonal) = 5 K |
| X-ray diffraction: mass absorption coefficients (µ/ρ) /cm2g-1 : |
CuKα 30.1 MoKα 3.21 |
| Neutron scattering length, b/10-12cm: |
0.358 |
| Thermal neutron capture cross-section, a/barns: |
0.530 |
Geological data
| Minerals: |
Sodium occurs in many minerals but these are not mined as a source of sodium compounds. |
| Mineral |
Formula |
Density |
Hardness |
Crystal apperance |
| Halite(rock salt) |
NaCl |
2.168 |
2 |
cub., vit. usually colorless |
| Trona |
Na3(CO3)(HCO3).2H2O |
2.14 |
2.5 - 3 |
mon., vit. colorless |
| Chief ore: |
halite, trona |
| World production: |
c. 200 000 (sodium metal); 168 x 106 (salt); 26 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 sticks stored under mineral oil. Warning! |
| Abundances |
|
| Sun: |
1.91 x 106 (relative to H = 1 x 1023) |
| Earth's crust: |
23 000 p.p.m. |
| Seawater: |
10 500 p.p.m. |
| Residence time: |
1x 108 years |
| Classification: |
accumulating |
| Oxidation state: |
I |
Other sizes and specifications on request
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