Term: Silicon
**History and Discovery of Silicon**:
– Silicon has been utilized for thousands of years in various civilizations.
– Predynastic Egyptians and ancient Chinese used silicon in various forms.
– Antoine Lavoisier, Sir Humphry Davy, and Jöns Jacob Berzelius played key roles in the discovery of silicon.
– Important milestones include the isolation of amorphous silicon and the discovery of silicon tetrachloride.
**Abundance and Economic Impact**:
– Silicon is the eighth most common element in the universe by mass.
– It is rarely found as a pure element in the Earth’s crust, with silicate minerals being more prevalent.
– Silicon plays a crucial role in modern technology, particularly in semiconductor electronics.
– The semiconductor market is projected to reach $726.73 billion by 2027, highlighting its economic significance.
**Biological Importance and Characteristics**:
– Silicon is essential in biology, with roles in skeletal structures of sea sponges and plant tissues.
– It is a semiconductor with unique physical and atomic characteristics.
– Silicon crystallizes in a diamond cubic lattice structure and has specific ionization energies and covalent radii.
– Electrical properties include its semiconductor nature and the formation of p–n junctions for electronic devices.
**Silicon Applications and Silicon Isotopes**:
– Silicon is widely used in the semiconductor industry, solar cell manufacturing, and integrated circuits.
– Silicon isotopes have various half-lives and decay modes, with implications for nuclear spectroscopy.
– Its applications extend to glass, ceramics, concrete, and technology advancements in various sectors.
**Chemical Properties and Structural Motifs**:
– Silicon reacts with specific elements and compounds to form silicates, silicides, and other chemical products.
– Structural motifs in silicon chemistry include tetrahedral coordination and differences from carbon chemistry.
– Silicon’s lower electronegativity, catenation tendency, and orbital properties contribute to its distinct chemical behavior.
– Comparisons with carbon chemistry highlight differences in bond energies, stability of compounds, and coordination characteristics.
Silicon is a chemical element; it has 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 (Si) element is a significant element that is essential for several physiological and metabolic processes in plants. Si is widely regarded as the predominant semiconductor material due to its versatile applications in various electrical devices such as transistors, solar cells, integrated circuits, and others. These may be due to its significant band gap, expansive optical transmission range, extensive absorption spectrum, surface roughening, and effective anti-reflection coating.
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| Pronunciation | ||||||||||||||||||||||||||||||||||||
| Allotropes | see Allotropes of silicon | |||||||||||||||||||||||||||||||||||
| Appearance | crystalline, reflective with bluish-tinged faces | |||||||||||||||||||||||||||||||||||
| Standard atomic weight Ar°(Si) | ||||||||||||||||||||||||||||||||||||
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| Silicon in the periodic table | ||||||||||||||||||||||||||||||||||||
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| Atomic number (Z) | 14 | |||||||||||||||||||||||||||||||||||
| Group | group 14 (carbon group) | |||||||||||||||||||||||||||||||||||
| Period | period 3 | |||||||||||||||||||||||||||||||||||
| Block | p-block | |||||||||||||||||||||||||||||||||||
| 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 (at 20° C) | 2.329085 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
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| Atomic properties | ||||||||||||||||||||||||||||||||||||
| Oxidation states | −4, −3, −2, −1, 0, +1, +2, +3, +4 (an amphoteric oxide) | |||||||||||||||||||||||||||||||||||
| Electronegativity | Pauling scale: 1.90 | |||||||||||||||||||||||||||||||||||
| Ionization energies |
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| Atomic radius | empirical: 111 pm | |||||||||||||||||||||||||||||||||||
| Covalent radius | 111 pm | |||||||||||||||||||||||||||||||||||
| Van der Waals radius | 210 pm | |||||||||||||||||||||||||||||||||||
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| Other properties | ||||||||||||||||||||||||||||||||||||
| Natural occurrence | primordial | |||||||||||||||||||||||||||||||||||
| Crystal structure | face-centered diamond-cubic (cF8) | |||||||||||||||||||||||||||||||||||
| Lattice constant |  | |||||||||||||||||||||||||||||||||||
| Thermal expansion | 2.556×10−6/K (at 20 °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 | |||||||||||||||||||||||||||||||||||
| Molar 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 | |||||||||||||||||||||||||||||||||||
| Speed of sound thin rod | 8433 m/s (at 20 °C) | |||||||||||||||||||||||||||||||||||
| 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) | |||||||||||||||||||||||||||||||||||
| Isotopes of silicon | ||||||||||||||||||||||||||||||||||||
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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 throughout 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 (<15%) 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.
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.