Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, lead, and flerovium are below it. It is relatively unreactive.

Silicon, 14Si
Silicon
Pronunciation
Allotropessee Allotropes of silicon
Appearancecrystalline, reflective with bluish-tinged faces
Standard atomic weight Ar°(Si)
  • [28.084, 28.086]
  • 28.085±0.001 (abridged)[1]
Silicon in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
C

Si

Ge
aluminiumsiliconphosphorus
Atomic number (Z)14
Groupgroup 14 (carbon group)
Periodperiod 3
Block  p-block
Electron configuration[Ne] 3s2 3p2
Electrons per shell2, 8, 4
Physical properties
Phase at STPsolid
Melting point1687 K (1414 °C, 2577 °F)
Boiling point3538 K (3265 °C, 5909 °F)
Density (near r.t.)2.3290 g/cm3
when liquid (at m.p.)2.57 g/cm3
Heat of fusion50.21 kJ/mol
Heat of vaporization383 kJ/mol
Molar heat capacity19.789 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1908 2102 2339 2636 3021 3537
Atomic properties
Oxidation states−4, −3, −2, −1, 0,[2] +1,[3] +2, +3, +4 (an amphoteric oxide)
ElectronegativityPauling scale: 1.90
Ionization energies
  • 1st: 786.5 kJ/mol
  • 2nd: 1577.1 kJ/mol
  • 3rd: 3231.6 kJ/mol
  • (more)
Atomic radiusempirical: 111 pm
Covalent radius111 pm
Van der Waals radius210 pm
Spectral lines of silicon
Other properties
Natural occurrenceprimordial
Crystal structure face-centered diamond-cubic
Speed of sound thin rod8433 m/s (at 20 °C)
Thermal expansion2.6 µm/(m⋅K) (at 25 °C)
Thermal conductivity149 W/(m⋅K)
Electrical resistivity2.3×103 Ω⋅m (at 20 °C)[4]
Band gap1.12 eV (at 300 K)
Magnetic orderingdiamagnetic[5]
Molar magnetic susceptibility−3.9×10−6 cm3/mol (298 K)[6]
Young's modulus130–188 GPa[7]
Shear modulus51–80 GPa[7]
Bulk modulus97.6 GPa[7]
Poisson ratio0.064–0.28[7]
Mohs hardness6.5
CAS Number7440-21-3
History
Namingafter Latin silex or silicis, meaning 'flint'
PredictionAntoine Lavoisier (1787)
Discovery and first isolationJöns Jacob Berzelius[8][9] (1823)
Named byThomas Thomson (1817)
Main isotopes of silicon
Iso­tope Decay
abun­dance half-life (t1/2) mode pro­duct
28Si 92.2% stable
29Si 4.7% stable
30Si 3.1% stable
31Si trace 2.62 h β 31P
32Si trace 153 y β 32P
 Category: Silicon
| references

Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its oxides form a family of anions known as silicates. Its melting and boiling points of 1414 °C and 3265 °C, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron.

Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust (about 28% by mass), after oxygen.

Most silicon is used commercially without being separated, often with very little processing of the natural minerals. Such use includes industrial construction with clays, silica sand, and stone. Silicates are used in Portland cement for mortar and stucco, and mixed with silica sand and gravel to make concrete for walkways, foundations, and roads. They are also used in whiteware ceramics such as porcelain, and in traditional silicate-based soda-lime glass and many other specialty glasses. Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. Silicon is the basis of the widely used synthetic polymers called silicones.

The late 20th century to early 21st century has been described as the Silicon Age (also known as the Digital Age or Information Age) because of the large impact that elemental silicon has on the modern world economy. The small portion of very highly purified elemental silicon used in semiconductor electronics (<10%[citation needed]) is essential to the transistors and integrated circuit chips used in most modern technology such as smartphones and other computers. In 2019, 32.4% of the semiconductor market segment was for networks and communications devices, and the semiconductors industry is projected to reach $726.73 billion by 2027. [10]

Silicon is an essential element in biology. Only traces are required by most animals, but some sea sponges and microorganisms, such as diatoms and radiolaria, secrete skeletal structures made of silica. Silica is deposited in many plant tissues.[11]


Share this article:

This article uses material from the Wikipedia article Silicon, and is written by contributors. Text is available under a CC BY-SA 4.0 International License; additional terms may apply. Images, videos and audio are available under their respective licenses.