Silicon (Si)

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Silicon 14Si28.086

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.



Silicon single crystal properties

State: single crystal
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

Materials properties

Density: 2.33 g/cm3
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: 0.42
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 data

Biological role: Silicon is essential to some species and possibly to humans.
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


Geological data

MineralFormulaDensityHardnessCrystal 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.
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.


Sun: 4.47 x 107(relative to H = 1 x 1012)
Earth's crust: 277 100 p.p.m.
Residence time:  
Classification: recycled
Oxidation state: IV

Source: Emsley, J. (1998) The Elements (3rd Edition)

Overview of elements with access to our shop

1 18
2 13 14 15 16 17
Li Be B C
Na Mg 3 4 5 6 7 8 9 10 11 12 Al Si P S
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se
Rb Sr Y Zr Nb Mo
Ru Rh Pd Ag Cd In Sn Sb Te I
Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi
Ce Pr Nd
Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

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