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Discovered in 1824 by J.J. Berzelius at Stockholm, Sweden.
[Latin, silicis = flint]
French: Silicium
German: Silizium
Italian: Silicio
Spanish: Silicio
Description: Black amorphous silicon is obtained by the reduction of sand (SiO2) with carbon. Ultrapure crystals if silicon have a blue-grey metallic sheen. Bulk silicon is unreactive towards oxygen, water and acids (exept HF), but dissolves in hot alkalis. Silicon is used in semiconductors, alloys and polymers.
State: | single crystal |
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Crystal structure: | diamond |
Production method: | Czochralski, Floating zone |
Standard size: | Diameter 20-80mm thickness 1mm |
Orientation: | (110) and (111) |
Orientation accuracy: | <2°, <1°, <0.4° or <0.1° |
Polishing: | as cut, one or two sides polished |
Roughness of surface: | <0.03µm |
Purity: | 99.999% |
Typical analysis (ppm): | C 3 H < 1 O 9 N < 5 Cu 1.60 Fe 1.80 Ni < 1 Pb 0.30 Si 0.30 Ga, Hf and Ta are below the detection limit |
Density: | 2.33 g/cm3 |
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Melting point: | 1409.85 °C / 1683 °K |
Boiling point: | 2354.85 °C / 2628 °K |
Molar volume: | 12.06 cm3 |
Thermal conductivity: | 148 [300 K] Wm-1K-1 |
Coefficient of linear thermal expansion: | 4.2 x 10-6 K-1 |
Electrical resistivity: | 0.001x 10-8 [273 K] Wm |
Mass magnetic susceptibility: | -1.8 x 10-9(s) kg-1m3 |
Young's modulus: | 113 GPa |
Rigidity modulus: | 39.7 GPa |
Bulk modulus: | n.a. GPa |
Poisson's ratio: | 0.05-0.42 |
Radii: | Si4+ 26; Si4- 271 atomic 117; covalent 117; van de |
Electronegativity: | 1.90 (Pauling); 1.74 (Allred); 4.77 eV (absolute) |
Effective nuclear charge: | 4.15 (Slater); 4.29 (Clementi); 4.48 (Froese-Fischer) |
Number of Isotopes (incl. nuclear isomers): | 11 |
Issotope mass range: | 24 -> 34 |
Crystal structure, (cell dimentions / pm), space group | diamond |
X-ray diffraction: mass absorption coefficients: | CuKα 60.6 (µ/r) / cm2g-1 MoKα 6.44 (µ/r) / cm2g-1 |
Neutron scattering length: | 0.41543 b/10-12 cm |
Thermal neutron capture cross-section: | 0.171 sa / barns |
Biological role: | Silicon is essential to some species and possibly to humans. |
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Toxicity | |
Toxic intake: | |
Lethal intake: | |
Hazards: | The fibres of some silicates, such as asbestos-type minerals, are carcinogenic. |
Level in humans | |
Blood: | 3.9 mg dm-3 |
Bone: | 17 p.p.m. |
Liver: | 12 - 120 p.p.m. |
Muscle: | 100 - 200 p.p.m. |
Daily dietary intake: | 18 - 1200 mg |
Total mass of element in average [70 kg] person: | c. 1 g |
Mineral | Formula | Density | Hardness | Crystal apperance |
---|---|---|---|---|
Cristobalite | SiO2 | 2.33 | n.a. | tet., vitreous/white |
Opal | SiO2.nH2O | 2 | 5.5 - 6.5 | amor., transp./col./white |
Quartz | a-SiO2 | 2.655 | 7 | rhom., vit., colourless |
Tridymite | SiO2 | 2.26 | 7 | mon., vit., colourless/white |
Chief ore: | quartz (most common mineral on earth); also talc, mica. |
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World production: | |
Main mining areas: | talc in Austria, Italy, India, South Africa, Australia; mica in Cananda, USA, India, Brazil |
Reserves: | unlimited |
Specimen: | available as powder, pieces or lumps. Safe. |
Abundances | |
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Sun: | 4.47 x 107(relative to H = 1 x 1012) |
Earth's crust: | 277 100 p.p.m. |
Seawater: | |
Residence time: | |
Classification: | recycled |
Oxidation state: | IV |
Source: Emsley, J. (1998) The Elements (3rd Edition)