Silicon

Silicon (Si)

Metalloid element belonging to group 14 of the periodic table. It is the second most abundant element in the Earth's crust, making up 25.7% of it by weight. Chemically less reactive than carbon. First identified by Lavoisier in 1787 and first isolated in 1823 by Berzelius.
Atomic Number14
Atomic Weight28.085
Mass Number28
Group14
Period3
Blockp
Protons14 p+
Neutrons14 n0
Electrons14 e-
SiliconCroda.jpg Silicon-unit-cell-3D-balls.png Animated Bohr Model Enhanced Bohr Model Bohr Model Orbital Diagram

Properties

Atomic Radius
110 pm
Atomic Volume
Covalent Radius
115.99999999999999 pm
Metallic Radius
117 pm
Ionic Radius
26 pm
Crystal Radius
40 pm
Van der Waals radius
210 pm
Density
2.3296 g/cm³
Boiling Point
2,628 K
Melting Point
1,683 K
Electrons per shell2, 8, 4
Electronegativity
1.9
Electrophilicity
1.6827934805483 eV/particle
Proton Affinity
837 kJ/mol
Electron Affinity
1.3895211 eV/particle
Ionization Potential
8.151683 eV/particle
Heat of Vaporization
383 kJ/mol
Heat of Fusion
50.6 kJ/mol
Heat of Formation
450 kJ/mol
Molar Heat Capacity
19.99 J/(mol K)
Specific Heat Capacity
0.712 J/(g⋅K)
Thermal Conductivity
Gas Basicity
814.1 kJ/mol
Dipole Polarizability
37.3 a₀
C6 Dispersion Coefficient
305 a₀
Oxidation States-4, -3, -2, -1, 1, 2, 3, 4
Color
Gray
Crystal StructureTetrahedral Packing (DIA)
Lattice Constant
5.43 Å
Bulk Modulus
Electrical Resistivity
Electron Configuration[Ne] 3s2 3p2
Magnetic Ordering
Magnetic Susceptibility
PhaseSolid
Poisson Ratio
Shear Modulus
Young's Modulus
Allotropes
Alternate Names
Adiabatic Index
Appearance
Electric Conductivity
Critical Pressure
Critical Temperature
Curie Point
Electrical
Hardness
Magnetic Susceptibility
Magnetic
Neel Point
Neutron Cross Section
Neutron Mass Absorption
Gas Phase
Quantum Numbers
Refractive Index
Space Group
Speed of Sound
Superconducting Point
Thermal Expansion
Valence Electrons
Classification
CategoryMetalloids, Metalloids
CAS GroupIVB
IUPAC GroupIVA
Glawe Number85
Mendeleev Number88
Pettifor Number85
Geochemical Classmajor
Goldschmidt Classlitophile
Radioactivity
RadioactiveNo
Decay Mode
Half-Life
Lifetime
Abundance
Abundance in Earth's crust
282,000 mg/kg
Abundance in Oceans
2.2 mg/L
Abundance in Human Body
Abundance in Meteor
Abundance in Sun
Abundance in Universe0.07%

Isotopes of Silicon

Stable Isotopes
28Si 29Si 30Si
Unstable Isotopes
22Si 23Si 24Si 25Si 26Si 27Si 31Si 32Si 33Si 34Si 35Si 36Si 37Si 38Si 39Si 40Si 41Si 42Si 43Si 44Si

History

In 1800, Sir Humphry Davy thought silica to be a compound and not an element; but in 1811, Gay Lussac and Louis Jacques Thénard probably prepared impure amorphous silicon by heating potassium with silicon tetrafluoride. In 1824 Jöns Jakob Berzelius prepared amorphous silicon by the same general method. Henri Deville in 1854 first prepared crystalline silicon, the second allotropic form of the element. From the Latin word silex, silicis, flint

DiscoverersJöns Berzelius
Discovery LocationSweden
Discovery Year1824
Name OriginLatin: silex, silicus, (flint).
If breathed in as a fine silica/silicate dust, it may cause chronic respiratory problems
Silicon also has the unusual property that it expands as it freezes

Uses

In the form of sand and clay it is used to make concrete and brick; it is a useful refractory material for high-temperature work, and in the form of silicates it is used in making enamels, pottery, etc. Silica, as sand, is a principal ingredient of glass. Silicon chips are the basis of modern electronic and computing. Silicon carbide, more commonly called carborundum is used in abrasives. Used in glass as silicon dioxide (SiO2). Silicon carbide (SiC) is one of the hardest substances known and used in polishing. Also the crystalline form is used in semiconductors.

Sources

Makes up major portion of clay, granite, quartz (SiO2), and sand. Commercial production depends on a reaction between sand (SiO2) and carbon at a temperature of around 2200 °C.