chemical element with symbol Si and atomic number 14

Silicon is a chemical element. Its atomic number is 14 on the periodic table. Its symbol is Si. It is a hard, brittle crystalline solid. It is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table.

Silicon, 14Si
Appearancecrystalline, reflective with bluish-tinged faces
Standard atomic weight Ar, std(Si)[28.08428.086] conventional: 28.085
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


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,[1] +1,[2] +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
Color lines in a spectral range
Spectral lines of silicon
Other properties
Natural occurrenceprimordial
Crystal structureface-centered diamond-cubic
Diamond cubic crystal structure for silicon
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)[3]
Band gap1.12 eV (at 300 K)
Magnetic orderingdiamagnetic[4]
Magnetic susceptibility−3.9·10−6 cm3/mol (298 K)[5]
Young's modulus130–188 GPa[6]
Shear modulus51–80 GPa[6]
Bulk modulus97.6 GPa[6]
Poisson ratio0.064–0.28[6]
Mohs hardness6.5
CAS Number7440-21-3
Namingafter Latin 'silex' or 'silicis', meaning flint
PredictionAntoine Lavoisier (1787)
Discovery and first isolationJöns Jacob Berzelius[7][8] (1823)
Named byThomas Thomson (1817)
Main isotopes of silicon
Iso­tope Abun­dance Half-life (t1/2) Decay 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 Category: Silicon
| references
Small grains of silicon because it has been crushed. This is not the silicon used in computers.
A thin cut of a large crystal of silicon that is very smooth. This is the type of silicon can be used in computers because it is very pure.

Silicon looks like a metal, but does not do everything a metal does, like conduct electricity very easily. Silicon is used as a great deal in today's computers and virtually every electronic device. Germanium can also be used in computers, but silicon is easier to find.

There is a lot of silicon on the Earth. At the beach, there is silicon in the form of sand. Sand is a compound of silicon known as silicon dioxide or silica. Glass is made by heating sand (or silicon dioxide) hot enough.[9] The glass can have different colours by adding coloured compounds. Silicon also makes up a lot of different rocks and minerals, and they are known as silicates.

Silicon in computersEdit

Silicon is a semiconductor, and much used in computers. A super-pure isotope of silicon, silicon-28, can now be made 40 times more pure than before. It is very important for the next big development in computers. This stores "qubits" in atoms of another element, like phosphorous, embedded in a tiny layer of ultra-pure silicon-28. These qubits can simultaneously encode a one and a zero, for incredibly fast and complex calculations.[10]

Related pagesEdit


  1. "New Type of Zero-Valent Tin Compound". Chemistry Europe. 27 August 2016.
  2. Ram, R. S.; et al. (1998). "Fourier Transform Emission Spectroscopy of the A2D–X2P Transition of SiH and SiD" (PDF). J. Mol. Spectr. 190 (2): 341–352. doi:10.1006/jmsp.1998.7582. PMID 9668026.
  3. Eranna, Golla (2014). Crystal Growth and Evaluation of Silicon for VLSI and ULSI. CRC Press. p. 7. ISBN 978-1-4822-3281-3.
  4. Magnetic susceptibility of the elements and inorganic compounds, in Lide, D. R., ed. (2005). CRC Handbook of Chemistry and Physics (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
  5. Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
  6. 6.0 6.1 6.2 6.3 Hopcroft, Matthew A.; Nix, William D.; Kenny, Thomas W. (2010). "What is the Young's Modulus of Silicon?". Journal of Microelectromechanical Systems. 19 (2): 229. doi:10.1109/JMEMS.2009.2039697.
  7. Weeks, Mary Elvira (1932). "The discovery of the elements: XII. Other elements isolated with the aid of potassium and sodium: beryllium, boron, silicon, and aluminum". Journal of Chemical Education. 9 (8): 1386–1412. Bibcode:1932JChEd...9.1386W. doi:10.1021/ed009p1386.
  8. Voronkov, M. G. (2007). "Silicon era". Russian Journal of Applied Chemistry. 80 (12): 2190. doi:10.1134/S1070427207120397.
  9. "Glass Crusher Machines". Retrieved 24 May 2016. CS1 maint: discouraged parameter (link)
  10. Webb, Jonathan 2014. Purer-than-pure silicon solves problem for quantum tech. BBC News Science & Environment [1]