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Silicon
 
General
Name, symbol, number silicon, Si, 14
Chemical series metalloids
Group, period, block 14, 3, p
Appearance as coarse powder,
dark grey with bluish tinge

 
Standard atomic weight 28.0855(3) g·mol−1
Electron configuration [Ne] 3s2 3p2
Electrons per shell 2, 8, 4
Physical properties
Phase solid
Density (near r.t.) 2.33 g·cm−3
Liquid density at m.p. 2.57 g·cm−3
Melting point 1687 K
(1414 °C, 2577 °F)
Boiling point 3538 K
(3265 °C, 5909 °F)
Heat of fusion 50.21 kJ·mol−1
Heat of vaporization 359 kJ·mol−1
Heat capacity (25 °C) 19.789 J·mol−1·K−1
Vapor pressure P/Pa 1 10 100 1 k 10 k 100 k
at T/K 1908 2102 2339 2636 3021 3537
 
Atomic properties
Crystal structure Diamond
Oxidation states 4
(amphoteric oxide)
Electronegativity 1.90 (Pauling scale)
Ionization energies
(more) 1st: 786.5 kJ·mol−1
2nd: 1577.1 kJ·mol−1
3rd: 3231.6 kJ·mol−1
Atomic radius 110 pm
Atomic radius (calc.) 111 pm
Covalent radius 111 pm
Van der Waals radius 210 pm
Miscellaneous
Magnetic ordering nonmagnetic
Thermal conductivity (300 K) 149 W·m−1·K−1
Thermal expansion (25 °C) 2.6 µm·m−1·K−1
Speed of sound (thin rod) (20 °C) 8433 m/s
Young's modulus 150 GPa
Bulk modulus 100 GPa
Mohs hardness 6.5
CAS registry number 7440-21-3
Band gap energy at 300 K 1.12 eV
Selected isotopes
Main article: Isotopes of silicon iso NA half-life DM DE (MeV) DP
28Si 92.23% Si is stable with 14 neutrons
29Si 4.67% Si is stable with 15 neutrons
30Si 3.1% Si is stable with 16 neutrons
32Si syn 170 y β- 13.020 32P
 
References
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Not to be confused with Silicone.
Silicon (IPA: /ˈsɪlikən/, Latin: silicium) is the chemical element that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. As the eighth most common element in the universe by mass, silicon occasionally occurs as the pure free element in nature, but is more widely distributed in dusts, planetoids and planets as various forms of silicon dioxide or silicate. On Earth, silicon is the second most abundant element (after oxygen) in the crust, making up 25.7% of the crust by mass.

Silicon has many industrial uses. Elemental silicon is the principal component of most semiconductor devices, most importantly integrated circuits or microchips. Silicon is widely used in semiconductors because it remains a semiconductor at higher temperatures than the semiconductor germanium and because its native oxide is easily grown in a furnace and forms a better semiconductor/dielectric interface than almost all other material combinations.

In the form of silica and silicates, silicon forms useful glasses, cements, and ceramics. It is also a component of silicones, a class-name for various synthetic plastic substances made of silicon, oxygen, carbon and hydrogen, often confused with silicon itself.

Silicon is an essential element in biology, although only tiny traces of it appear to be required by animals. It is much more important to the metabolism of plants, particularly many grasses, and silicic acid (a type of silica) forms the basis of the striking array of protective shells of the microscopic diatoms.

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