Silicium

Silicon,  ₁₄Si

General properties
Pronunciation	/ˈsɪlɪkən/ SIL-ik-ən
Appearance	crystalline, reflective with bluish-tinged faces
Standard atomic weight (Ar, standard)	[7001280840000000000♠28.084, 7001280860000000000♠28.086] conventional: 7001280850000000000♠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 C ↑ Si ↓ Ge aluminium ← silicon → phosphorus
Atomic number (Z)	14
Group, period	group 14 (carbon group), period 3
Block	p-block
Element category	metalloid
Electron configuration	[Ne] 3s2 3p2
Electrons per shell	2, 8, 4
Physical properties
Phase (at STP)	solid
Melting point	1687 K ​(1414 °C, ​2577 °F)
Boiling point	3538 K ​(3265 °C, ​5909 °F)
Density (near r.t.)	2.3290 g/cm3
when liquid (at m.p.)	2.57 g/cm3
Heat of fusion	50.21 kJ/mol
Heat of vaporization	383 kJ/mol
Molar heat capacity	19.789 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 −1, −2, −3, −4 ​(an amphoteric oxide)
Electronegativity	Pauling scale: 1.90
Ionization energies	1st: 786.5 kJ/mol 2nd: 1577.1 kJ/mol 3rd: 3231.6 kJ/mol (more)
Atomic radius	empirical: 111 pm
Covalent radius	111 pm
Van der Waals radius	210 pm
Spectral lines
Miscellanea
Crystal structure	​face-centered diamond-cubic
Speed of sound thin rod	8433 m/s (at 20 °C)
Thermal expansion	2.6 µm/(m·K) (at 25 °C)
Thermal conductivity	149 W/(m·K)
Electrical resistivity	2.3×103 Ω·m (at 20 °C)
Band gap	1.12 eV (at 300 K)
Magnetic ordering	diamagnetic
Magnetic susceptibility	−3.9·10−6 cm3/mol (298 K)
Young's modulus	130–188 GPa
Shear modulus	51–80 GPa
Bulk modulus	97.6 GPa
Poisson ratio	0.064–0.28
Mohs hardness	6.5
CAS Number	7440-21-3
History
Naming	after Latin 'silex' or 'silicis', meaning flint
Prediction	Antoine Lavoisier (1787)
Discovery and first isolation	Jöns Jacob Berzelius (1823)
Named by	Thomas 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
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Spectral lines

Silicon is a chemical element with symbol Si and atomic number 14. A hard and brittle crystalline solid with a blue-grey metallic lustre, it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table, along with carbon above it and germanium, tin, and lead below. It is rather unreactive, though less so than germanium, and has a very large chemical affinity for oxygen; as such, it was first prepared and characterized in pure form only in 1823 by Jöns Jakob Berzelius.

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 most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. Over 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, and often with 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 quartz-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.