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112-461: The sands formed from the decomposition of volcanic rock ( basalt ) gullies into clay , further transformed into ferralitic soil by total hydrolysis ; the two main elements of the resulting soil, iron and aluminium , are responsible for red/anthracite and blue/purplish colours respectively. The different shades of colour are believed to be a consequence of the molten volcanic rock cooling down at different external temperatures (hence rates), but

224-502: A calque of the Latin root (e.g. Russian кремний , from кремень "flint"; Greek πυρίτιο from πυρ "fire"; Finnish pii from piikivi "flint", Czech křemík from křemen "quartz", "flint"). Gay-Lussac and Thénard are thought to have prepared impure amorphous silicon in 1811, through the heating of recently isolated potassium metal with silicon tetrafluoride , but they did not purify and characterize

336-618: A field-effect amplifier made from germanium and silicon, but he failed to build a working device, before eventually working with germanium instead. The first working transistor was a point-contact transistor built by John Bardeen and Walter Brattain later that year while working under Shockley. In 1954, physical chemist Morris Tanenbaum fabricated the first silicon junction transistor at Bell Labs . In 1955, Carl Frosch and Lincoln Derick at Bell Labs accidentally discovered that silicon dioxide ( SiO 2 ) could be grown on silicon. By 1957 Frosch and Derick published their work on

448-425: A hexagonal close-packed allotrope at about 40  gigapascals known as Si–VII (the standard modification being Si–I). An allotrope called BC8 (or bc8), having a body-centred cubic lattice with eight atoms per primitive unit cell ( space group 206 ), can be created at high pressure and remains metastable at low pressure. Its properties have been studied in detail. Silicon boils at 3265 °C: this, while high,

560-457: A vesicular texture caused by voids left by volatiles trapped in the molten lava . Pumice is a highly vesicular rock produced in explosive volcanic eruptions . Most modern petrologists classify igneous rocks, including volcanic rocks, by their chemistry when dealing with their origin. The fact that different mineralogies and textures may be developed from the same initial magmas has led petrologists to rely heavily on chemistry to look at

672-430: A black glassy substance called obsidian . When filled with bubbles of gas, the same lava may form the spongy appearing pumice . Allowed to cool slowly, it forms a light-colored, uniformly solid rock called rhyolite. The lavas, having cooled rapidly in contact with the air or water, are mostly finely crystalline or have at least fine-grained ground-mass representing that part of the viscous semi-crystalline lava flow that

784-410: A close analogy to hot solutions of salts in water, which, when they approach the saturation temperature, first deposit a crop of large, well-formed crystals (labile stage) and subsequently precipitate clouds of smaller less perfect crystalline particles (metastable stage). In igneous rocks the first generation of crystals generally forms before the lava has emerged to the surface, that is to say, during

896-410: A common Fermi level; electrons flow from n to p, while holes flow from p to n, creating a voltage drop. This p–n junction thus acts as a diode that can rectify alternating current that allows current to pass more easily one way than the other. A transistor is an n–p–n junction, with a thin layer of weakly p-type silicon between two n-type regions. Biasing the emitter through a small forward voltage and

1008-476: A conductivity (i.e., too high a resistivity ) to be used as a circuit element in electronics. In practice, pure silicon is doped with small concentrations of certain other elements, which greatly increase its conductivity and adjust its electrical response by controlling the number and charge ( positive or negative ) of activated carriers. Such control is necessary for transistors , solar cells , semiconductor detectors , and other semiconductor devices used in

1120-402: A ferrosilicon alloy, and only approximately 20% is refined to metallurgical grade purity (a total of 1.3–1.5 million metric tons/year). An estimated 15% of the world production of metallurgical grade silicon is further refined to semiconductor purity. This typically is the "nine-9" or 99.9999999% purity, nearly defect-free single crystalline material. Monocrystalline silicon of such purity

1232-459: A good supplier will know what sort of volcanic rock they are selling. The sub-family of rocks that form from volcanic lava are called igneous volcanic rocks (to differentiate them from igneous rocks that form from magma below the surface, called igneous plutonic rocks ). The lavas of different volcanoes, when cooled and hardened, differ much in their appearance and composition. If a rhyolite lava-stream cools quickly, it can quickly freeze into

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1344-405: A handful of sands of different colours and mixes them together, as they'll eventually separate into a layered spectrum. The place has become one of Mauritius' main tourist attractions since the 1960s. Nowadays, the dunes are protected by a wooden fence and visitors are not allowed to climb on them, although they can look at the scenery from observation outposts placed along the fence. Curio shops in

1456-462: A paramorph of augite and magnetite, which may partially or completely substitute for the original crystal but still retains its characteristic outlines. The mechanical behaviour of volcanic rocks is complicated by their complex microstructure. For example, attributes such as the partitioning of the void space (pores and microcracks), pore and crystal size and shape, and hydrothermal alteration can all vary widely in volcanic rocks and can all influence

1568-400: A purely notional figure given the lack of a simple Si cation in reality. At standard temperature and pressure, silicon is a shiny semiconductor with a bluish-grey metallic lustre; as typical for semiconductors, its resistivity drops as temperature rises. This arises because silicon has a small energy gap ( band gap ) between its highest occupied energy levels (the valence band) and

1680-455: A structural complexity unseen in oxocarbons . Silicon tends to resemble germanium far more than it does carbon, and this resemblance is enhanced by the d-block contraction , resulting in the size of the germanium atom being much closer to that of the silicon atom than periodic trends would predict. Nevertheless, there are still some differences because of the growing importance of the divalent state in germanium compared to silicon. Additionally,

1792-542: A structural material for their skeletons. Some plants accumulate silica in their tissues and require silicon for their growth, for example rice . Silicon may be taken up by plants as orthosilicic acid (also known as monosilicic acid) and transported through the xylem , where it forms amorphous complexes with components of the cell wall. This has been shown to improve cell wall strength and structural integrity in some plants, thereby reducing insect herbivory and pathogenic infections. In certain plants, silicon may also upregulate

1904-485: A trend toward increasingly complex silicate units with cooling, and the introduction of hydroxide and fluoride anions in addition to oxides. Many metals may substitute for silicon. After these igneous rocks undergo weathering , transport, and deposition, sedimentary rocks like clay, shale, and sandstone are formed. Metamorphism also may occur at high temperatures and pressures, creating an even vaster variety of minerals. There are four sources for silicon fluxes into

2016-502: A volcanic rock's origin. The chemical classification of igneous rocks is based first on the total content of silicon and alkali metals ( sodium and potassium ) expressed as weight fraction of silica and alkali oxides ( K 2 O plus Na 2 O ). These place the rock in one of the fields of the TAS diagram . Ultramafic rock and carbonatites have their own specialized classification, but these rarely occur as volcanic rocks. Some fields of

2128-581: Is porcelain , which is based on the silicate mineral kaolinite . Traditional glass (silica-based soda–lime glass ) also functions in many of the same ways, and also is used for windows and containers. In addition, specialty silica based glass fibers are used for optical fiber , as well as to produce fiberglass for structural support and glass wool for thermal insulation . Silicones often are used in waterproofing treatments, molding compounds, mold- release agents , mechanical seals, high temperature greases and waxes, and caulking compounds. Silicone

2240-402: 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 is a significant element that

2352-425: Is a deep water Si gradient of greater than 0.3 parts per thousand. Si is most commonly associated with productivity in the oceans. Crystalline bulk silicon is rather inert, but becomes more reactive at high temperatures. Like its neighbour aluminium, silicon forms a thin, continuous surface layer of silicon dioxide ( SiO 2 ) that protects the metal from oxidation. Thus silicon does not measurably react with

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2464-432: Is a major structural motif in silicon chemistry just as it is for carbon chemistry. However, the 3p subshell is rather more diffuse than the 2p subshell and does not hybridise so well with the 3s subshell. As a result, the chemistry of silicon and its heavier congeners shows significant differences from that of carbon, and thus octahedral coordination is also significant. For example, the electronegativity of silicon (1.90)

2576-401: Is a molten liquid and rock is solid). "Lava stone" may describe anything from a friable silicic pumice to solid mafic flow basalt, and is sometimes used to describe rocks that were never lava , but look as if they were (such as sedimentary limestone with dissolution pitting ). To convey anything about the physical or chemical properties of the rock, a more specific term should be used;

2688-496: Is also sometimes used in breast implants , contact lenses, explosives and pyrotechnics . Silly Putty was originally made by adding boric acid to silicone oil . Other silicon compounds function as high-technology abrasives and new high-strength ceramics based upon silicon carbide . Silicon is a component of some superalloys . Elemental silicon is added to molten cast iron as ferrosilicon or silicocalcium alloys to improve performance in casting thin sections and to prevent

2800-428: Is conducted in the presence of scrap iron with low amounts of phosphorus and sulfur , producing ferrosilicon . Ferrosilicon, an iron-silicon alloy that contains varying ratios of elemental silicon and iron, accounts for about 80% of the world's production of elemental silicon, with China, the leading supplier of elemental silicon, providing 4.6 million tonnes (or 2/3rds of world output) of silicon, most of it in

2912-406: Is created when heat produces free electrons and holes, which in turn pass more current, which produces more heat). In addition, the insulating oxide of silicon is not soluble in water, which gives it an advantage over germanium (an element with similar properties which can also be used in semiconductor devices) in certain fabrication techniques. Monocrystalline silicon is expensive to produce, and

3024-411: Is dependent on two things: the initial composition of the primary magma and the subsequent differentiation. Differentiation of most magmas tends to increase the silica ( SiO 2 ) content, mainly by crystal fractionation . The initial composition of most magmas is basaltic , albeit small differences in initial compositions may result in multiple differentiation series. The most common of these series are

3136-453: Is deposited in many plant tissues. Owing to the abundance of silicon in the Earth's crust , natural silicon-based materials have been used for thousands of years. Silicon rock crystals were familiar to various ancient civilizations , such as the predynastic Egyptians who used it for beads and small vases , as well as the ancient Chinese . Glass containing silica was manufactured by

3248-484: Is deposited into the world's oceans each year. Of that value, 80–240 megatonnes are in the form of particulate silicon. The total amount of particulate silicon deposition into the ocean is still less than the amount of silicon influx into the ocean via riverine transportation. Aeolian inputs of particulate lithogenic silicon into the North Atlantic and Western North Pacific oceans are the result of dust settling on

3360-524: Is easily produced on Si surfaces by processes of thermal oxidation or local oxidation (LOCOS) , which involve exposing the element to oxygen under the proper conditions that can be predicted by the Deal–Grove model . Silicon has become the most popular material for both high power semiconductors and integrated circuits because it can withstand the highest temperatures and greatest electrical activity without suffering avalanche breakdown (an electron avalanche

3472-503: Is essential for several physiological and metabolic processes in plants. Silicon 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. Because of its high chemical affinity for oxygen, it

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3584-534: 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

3696-435: Is highly exothermic and hence requires no outside energy source. Hyperfine silicon is made at a higher purity than almost any other material: transistor production requires impurity levels in silicon crystals less than 1 part per 10 , and in special cases impurity levels below 1 part per 10 are needed and attained. Silicon nanostructures can directly be produced from silica sand using conventional metalothermic processes, or

3808-470: Is much less than that of carbon (2.55), because the valence electrons of silicon are further from the nucleus than those of carbon and hence experience smaller electrostatic forces of attraction from the nucleus. The poor overlap of 3p orbitals also results in a much lower tendency toward catenation (formation of Si–Si bonds) for silicon than for carbon, due to the concomitant weakening of the Si–Si bond compared to

3920-524: Is of use in NMR and EPR spectroscopy , as it is the only one with a nuclear spin ( I = ⁠ 1 / 2 ⁠ ). All three are produced in Type Ia supernovae through the oxygen-burning process , with Si being made as part of the alpha process and hence the most abundant. The fusion of Si with alpha particles by photodisintegration rearrangement in stars is known as the silicon-burning process ; it

4032-507: Is still lower than the temperature at which its lighter congener carbon sublimes (3642 °C) and silicon similarly has a lower heat of vaporisation than carbon, consistent with the fact that the Si–Si bond is weaker than the C–C bond. It is also possible to construct silicene layers analogous to graphene . Naturally occurring silicon is composed of three stable isotopes , Si (92.23%), Si (4.67%), and Si (3.10%). Out of these, only Si

4144-518: 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%)

4256-411: Is the last stage of stellar nucleosynthesis before the rapid collapse and violent explosion of the star in question in a type II supernova . Twenty-two radioisotopes have been characterized, the two stablest being Si with a half-life of about 150 years, and Si with a half-life of 2.62 hours. All the remaining radioactive isotopes have half-lives that are less than seven seconds, and

4368-508: Is the non-toxic, metal-free nature of silicon. Another application of silicon quantum dots is for sensing of hazardous materials. The sensors take advantage of the luminescent properties of the quantum dots through quenching of the photoluminescence in the presence of the hazardous substance. There are many methods used for hazardous chemical sensing with a few being electron transfer, fluorescence resonance energy transfer , and photocurrent generation. Electron transfer quenching occurs when

4480-532: Is used in building mortar and modern stucco , but more importantly, combined with silica sand, and gravel (usually containing silicate minerals such as granite), to make the concrete that is the basis of most of the very largest industrial building projects of the modern world. Silica is used to make fire brick , a type of ceramic. Silicate minerals are also in whiteware ceramics , an important class of products usually containing various types of fired clay minerals (natural aluminium phyllosilicates). An example

4592-486: Is used in the chemical industry. However, even greater purity is needed for semiconductor applications, and this is produced from the reduction of tetrachlorosilane (silicon tetrachloride) or trichlorosilane . The former is made by chlorinating scrap silicon and the latter is a byproduct of silicone production. These compounds are volatile and hence can be purified by repeated fractional distillation , followed by reduction to elemental silicon with very pure zinc metal as

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4704-618: Is usually justified only in production of integrated circuits, where tiny crystal imperfections can interfere with tiny circuit paths. For other uses, other types of pure silicon may be employed. These include hydrogenated amorphous silicon and upgraded metallurgical-grade silicon (UMG-Si) used in the production of low-cost, large-area electronics in applications such as liquid crystal displays and of large-area, low-cost, thin-film solar cells . Such semiconductor grades of silicon are either slightly less pure or polycrystalline rather than monocrystalline, and are produced in comparable quantities as

4816-521: Is usually produced by the Czochralski process , and is used to produce silicon wafers used in the semiconductor industry , in electronics, and in some high-cost and high-efficiency photovoltaic applications. Pure silicon is an intrinsic semiconductor , which means that unlike metals, it conducts electron holes and electrons released from atoms by heat; silicon's electrical conductivity increases with higher temperatures. Pure silicon has too low

4928-467: The Egyptians since at least 1500 BC, as well as by the ancient Phoenicians . Natural silicate compounds were also used in various types of mortar for construction of early human dwellings . In 1787, Antoine Lavoisier suspected that silica might be an oxide of a fundamental chemical element , but the chemical affinity of silicon for oxygen is high enough that he had no means to reduce

5040-446: The automotive industry . Silicon's importance in aluminium casting is that a significantly high amount (12%) of silicon in aluminium forms a eutectic mixture which solidifies with very little thermal contraction. This greatly reduces tearing and cracks formed from stress as casting alloys cool to solidity. Silicon also significantly improves the hardness and thus wear-resistance of aluminium. Most elemental silicon produced remains as

5152-746: The halogens ; fluorine attacks silicon vigorously at room temperature, chlorine does so at about 300 °C, and bromine and iodine at about 500 °C. Silicon does not react with most aqueous acids, but is oxidised and complexed by hydrofluoric acid mixtures containing either chlorine or nitric acid to form hexafluorosilicates . It readily dissolves in hot aqueous alkali to form silicates . At high temperatures, silicon also reacts with alkyl halides ; this reaction may be catalysed by copper to directly synthesise organosilicon chlorides as precursors to silicone polymers. Upon melting, silicon becomes extremely reactive, alloying with most metals to form silicides , and reducing most metal oxides because

5264-489: The heat of formation of silicon dioxide is so large. In fact, molten silicon reacts virtually with every known kind of crucible material (except its own oxide, SiO 2 ). This happens due to silicon's high binding forces for the light elements and to its high dissolving power for most elements. As a result, containers for liquid silicon must be made of refractory , unreactive materials such as zirconium dioxide or group 4, 5, and 6 borides. Tetrahedral coordination

5376-418: The lowest unoccupied molecular orbital (LUMO) is slightly lower in energy than the conduction band of the quantum dot, allowing for the transfer of electrons between the two, preventing recombination of the holes and electrons within the nanocrystals. The effect can also be achieved in reverse with a donor molecule having its highest occupied molecular orbital (HOMO) slightly higher than a valence band edge of

5488-455: The mantle makes up 68.1% of the Earth's mass and is composed mostly of denser oxides and silicates, an example being olivine , (Mg,Fe) 2 SiO 4 ; while the lighter siliceous minerals such as aluminosilicates rise to the surface and form the crust, making up 0.4% of the Earth's mass. The crystallisation of igneous rocks from magma depends on a number of factors; among them are

5600-409: The photocurrent emitted by the quantum dots instead of monitoring the photoluminescent display. If the concentration of the desired chemical increases then the photocurrent given off by the nanocrystals will change in response. Although silicon is readily available in the form of silicates , very few organisms use it directly. Diatoms , radiolaria , and siliceous sponges use biogenic silica as

5712-408: The pyroxenes . Bowen's reaction series correctly predicts the order of formation of the most common minerals in volcanic rocks. Occasionally, a magma may pick up crystals that crystallized from another magma; these crystals are called xenocrysts . Diamonds found in kimberlites are rare but well-known xenocrysts; the kimberlites do not create the diamonds, but pick them up and transport them to

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5824-562: The tholeiitic , calc-alkaline , and alkaline . Most volcanic rocks share a number of common minerals . Differentiation of volcanic rocks tends to increase the silica (SiO 2 ) content mainly by fractional crystallization . Thus, more evolved volcanic rocks tend to be richer in minerals with a higher amount of silica such as phyllo and tectosilicates including the feldspars, quartz polymorphs and muscovite . While still dominated by silicates, more primitive volcanic rocks have mineral assemblages with less silica, such as olivine and

5936-595: The 20th century saw the development of the chemistry and industrial use of siloxanes and the growing use of silicone polymers , elastomers , and resins . In the late 20th century, the complexity of the crystal chemistry of silicides was mapped, along with the solid-state physics of doped semiconductors . The first semiconductor devices did not use silicon, but used galena , including German physicist Ferdinand Braun 's crystal detector in 1874 and Indian physicist Jagadish Chandra Bose 's radio crystal detector in 1901. The first silicon semiconductor device

6048-533: The C–C bond: the average Si–Si bond energy is approximately 226 kJ/mol, compared to a value of 356 kJ/mol for the C–C bond. This results in multiply bonded silicon compounds generally being much less stable than their carbon counterparts, an example of the double bond rule . On the other hand, the presence of radial nodes in the 3p orbitals of silicon suggests the possibility of hypervalence , as seen in five and six-coordinate derivatives of silicon such as SiX 5 and SiF 6 . Lastly, because of

6160-535: The Earth's crust is composed of silicate minerals , which are compounds of silicon and oxygen, often with metallic ions when negatively charged silicate anions require cations to balance the charge. Many of these have direct commercial uses, such as clays, silica sand, and most kinds of building stone. Thus, the vast majority of uses for silicon are as structural compounds, either as the silicate minerals or silica (crude silicon dioxide). Silicates are used in making Portland cement (made mostly of calcium silicates) which

6272-427: The Earth's current land surface. Volcanic rocks are usually fine-grained or aphanitic to glass in texture. They often contain clasts of other rocks and phenocrysts . Phenocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye . Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix. Volcanic rocks often have

6384-624: The TAS diagram are further subdivided by the ratio of potassium oxide to sodium oxide. Additional classifications may be made on the basis of other components, such as aluminum or iron content. Volcanic rocks are also broadly divided into subalkaline, alkaline, and peralkaline volcanic rocks. Subalkaline rocks are defined as rocks in which SiO 2 < -3.3539 × 10 × A + 1.2030 × 10 × A - 1.5188 × 10 × A + 8.6096 × 10 × A - 2.1111 × A + 3.9492 × A + 39.0 where both silica and total alkali oxide content (A) are expressed as molar fraction . Because

6496-436: The TAS diagram uses weight fraction and the boundary between alkaline and subalkaline rock is defined in terms of molar fraction, the position of this curve on the TAS diagram is only approximate. Peralkaline volcanic rocks are defined as rocks having Na 2 O + K 2 O > Al 2 O 3 , so that some of the alkali oxides must be present as aegirine or sodic amphibole rather than feldspar . The chemistry of volcanic rocks

6608-399: The air below 900 °C, but formation of the vitreous dioxide rapidly increases between 950 °C and 1160 °C and when 1400 °C is reached, atmospheric nitrogen also reacts to give the nitrides SiN and Si 3 N 4 . Silicon reacts with gaseous sulfur at 600 °C and gaseous phosphorus at 1000 °C. This oxide layer nevertheless does not prevent reaction with

6720-646: The area sell small test-tubes filled up with the coloured earths. This Mauritius location article is a stub . You can help Misplaced Pages by expanding it . Volcanic rock Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano . Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks . For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In

6832-428: The ascent from the subterranean depths to the crater of the volcano. It has frequently been verified by observation that freshly emitted lavas contain large crystals borne along in a molten, liquid mass. The large, well-formed, early crystals ( phenocrysts ) are said to be porphyritic ; the smaller crystals of the surrounding matrix or ground-mass belong to the post-effusion stage. More rarely lavas are completely fused at

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6944-408: The behavior of its oxide compounds and its reaction with acids as well as bases (though this takes some effort), and is hence often referred to as a metalloid rather than a nonmetal. Germanium shows more, and tin is generally considered a metal. Silicon shows clear differences from carbon. For example, organic chemistry has very few analogies with silicon chemistry, while silicate minerals have

7056-480: The causes of their consistent spontaneous separation are yet to be fully clarified. The name "Seven Coloured Earth(s)" is a descriptive—rather than an official—name. Sources report many variations of this name, including "Chamarel Seven Coloured Earths", "Chamarel Coloured Earth(s)", "Coloured Earth", and Terres des Sept Couleurs in French . This phenomenon can also be observed, on a smaller scale, if one takes

7168-584: The central silicon atom shares an electron pair with each of the four atoms it is bonded to. The first four ionisation energies of silicon are 786.3, 1576.5, 3228.3, and 4354.4 kJ/mol respectively; these figures are high enough to preclude the possibility of simple cationic chemistry for the element. Following periodic trends , its single-bond covalent radius of 117.6 pm is intermediate between those of carbon (77.2 pm) and germanium (122.3 pm). The hexacoordinate ionic radius of silicon may be considered to be 40 pm, although this must be taken as

7280-418: The chemical composition of the magma, the cooling rate, and some properties of the individual minerals to be formed, such as lattice energy , melting point, and complexity of their crystal structure. As magma is cooled, olivine appears first, followed by pyroxene , amphibole , biotite mica, orthoclase feldspar , muscovite mica , quartz , zeolites , and finally, hydrothermal minerals. This sequence shows

7392-418: The collector through a large reverse voltage allows the transistor to act as a triode amplifier. Silicon crystallises in a giant covalent structure at standard conditions, specifically in a diamond cubic crystal lattice ( space group 227 ). It thus has a high melting point of 1414 °C, as a lot of energy is required to break the strong covalent bonds and melt the solid. Upon melting silicon contracts as

7504-410: The combustion synthesis approach. Such nanostructured silicon materials can be used in various functional applications including the anode of lithium-ion batteries (LIBs), other ion batteries, future computing devices like memristors or photocatalytic applications. Most silicon is used industrially without being purified, often with comparatively little processing from its natural form. More than 90% of

7616-400: The computer industry and other technical applications. In silicon photonics , silicon may be used as a continuous wave Raman laser medium to produce coherent light. In common integrated circuits , a wafer of monocrystalline silicon serves as a mechanical support for the circuits, which are created by doping and insulated from each other by thin layers of silicon oxide , an insulator that

7728-411: The conduction band either thermally or photolytically, creating an n-type semiconductor . Similarly, doping silicon with a group 13 element such as boron , aluminium , or gallium results in the introduction of acceptor levels that trap electrons that may be excited from the filled valence band, creating a p-type semiconductor . Joining n-type silicon to p-type silicon creates a p–n junction with

7840-520: The context of Precambrian shield geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks . Volcanic rocks and sediment that form from magma erupted into the air are called "pyroclastics," and these are also technically sedimentary rocks. Volcanic rocks are among the most common rock types on Earth's surface, particularly in the oceans. On land, they are very common at plate boundaries and in flood basalt provinces . It has been estimated that volcanic rocks cover about 8% of

7952-433: The crystal. It is clear that after the mineral had crystallized it was partly again dissolved or corroded at some period before the matrix solidified. Corroded phenocrysts of biotite and hornblende are very common in some lavas; they are surrounded by black rims of magnetite mixed with pale green augite. The hornblende or biotite substance has proved unstable at a certain stage of consolidation, and has been replaced by

8064-1763: The dominant materials during their respective ages of civilization . Because silicon is an important element in high-technology semiconductor devices, many places in the world bear its name. For example, the Santa Clara Valley in California acquired the nickname Silicon Valley , as the element is the base material in the semiconductor industry there. Since then, many other places have been similarly dubbed, including Silicon Wadi in Israel; Silicon Forest in Oregon; Silicon Hills in Austin, Texas; Silicon Slopes in Salt Lake City, Utah; Silicon Saxony in Germany; Silicon Valley in India; Silicon Border in Mexicali, Mexico; Silicon Fen in Cambridge, England; Silicon Roundabout in London; Silicon Glen in Scotland; Silicon Gorge in Bristol, England; Silicon Alley in New York City; and Silicon Beach in Los Angeles. A silicon atom has fourteen electrons . In

8176-498: The emitted electron carries up to 1.48  MeV of energy. The known isotopes of silicon range in mass number from 22 to 46. The most common decay mode of the isotopes with mass numbers lower than the three stable isotopes is inverse beta decay , primarily forming aluminium isotopes (13 protons) as decay products . The most common decay mode for the heavier unstable isotopes is beta decay, primarily forming phosphorus isotopes (15 protons) as decay products. Silicon can enter

8288-497: The first manufactured SiO 2 semiconductor oxide transistor: the first planar transistors, in which drain and source were adjacent at the same surface. The "Silicon Age" refers to the late 20th century to early 21st century. This is due to silicon being the dominant material of the Silicon Age (also known as the Digital Age or Information Age ), similar to how the Stone Age , Bronze Age and Iron Age were defined by

8400-408: The first volatile hydrides of silicon, synthesising trichlorosilane in 1857 and silane itself in 1858, but a detailed investigation of the silanes was only carried out in the early 20th century by Alfred Stock , despite early speculation on the matter dating as far back as the beginnings of synthetic organic chemistry in the 1830s. Similarly, the first organosilicon compound , tetraethylsilane,

8512-578: The form of ferrosilicon. It is followed by Russia (610,000 t), Norway (330,000 t), Brazil (240,000 t), and the United States (170,000 t). Ferrosilicon is primarily used by the iron and steel industry (see below ) with primary use as alloying addition in iron or steel and for de-oxidation of steel in integrated steel plants. Another reaction, sometimes used, is aluminothermal reduction of silicon dioxide, as follows: Leaching powdered 96–97% pure silicon with water results in ~98.5% pure silicon, which

8624-418: The formation of cementite where exposed to outside air. The presence of elemental silicon in molten iron acts as a sink for oxygen, so that the steel carbon content, which must be kept within narrow limits for each type of steel, can be more closely controlled. Ferrosilicon production and use is a monitor of the steel industry, and although this form of elemental silicon is grossly impure, it accounts for 80% of

8736-465: The formation of the Solar System . Silicon makes up 27.2% of the Earth's crust by weight, second only to oxygen at 45.5%, with which it always is associated in nature. Further fractionation took place in the formation of the Earth by planetary differentiation : Earth's core , which makes up 31.5% of the mass of the Earth, has approximate composition Fe 25 Ni 2 Co 0.1 S 3 ;

8848-522: The ground state, they are arranged in the electron configuration [Ne]3s 3p . Of these, four are valence electrons , occupying the 3s orbital and two of the 3p orbitals. Like the other members of its group, the lighter carbon and the heavier germanium , tin , and lead , it has the same number of valence electrons as valence orbitals: hence, it can complete its octet and obtain the stable noble gas configuration of argon by forming sp hybrid orbitals , forming tetrahedral SiX 4 derivatives where

8960-404: The ground-mass . Microscopic examination of the phenocrysts often reveals that they have had a complex history. Very frequently they show layers of different composition, indicated by variations in color or other optical properties; thus augite may be green in the center surrounded by various shades of brown; or they may be pale green centrally and darker green with strong pleochroism (aegirine) at

9072-430: The increasing energy gap between the valence s and p orbitals as the group is descended, the divalent state grows in importance from carbon to lead, so that a few unstable divalent compounds are known for silicon; this lowering of the main oxidation state, in tandem with increasing atomic radii, results in an increase of metallic character down the group. Silicon already shows some incipient metallic behavior, particularly in

9184-402: The long-range tetrahedral network of bonds breaks up and the voids in that network are filled in, similar to water ice when hydrogen bonds are broken upon melting. It does not have any thermodynamically stable allotropes at standard pressure, but several other crystal structures are known at higher pressures. The general trend is one of increasing coordination number with pressure, culminating in

9296-471: The lower Ge–O bond strength compared to the Si–O bond strength results in the absence of "germanone" polymers that would be analogous to silicone polymers. Silicon is the eighth most abundant element in the universe, coming after hydrogen , helium , carbon , nitrogen , oxygen , iron , and neon . These abundances are not replicated well on Earth due to substantial separation of the elements taking place during

9408-449: The lowest unoccupied ones (the conduction band). The Fermi level is about halfway between the valence and conduction bands and is the energy at which a state is as likely to be occupied by an electron as not. Hence pure silicon is effectively an insulator at room temperature. However, doping silicon with a pnictogen such as phosphorus , arsenic , or antimony introduces one extra electron per dopant and these may then be excited into

9520-440: The majority of these have half-lives that are less than one-tenth of a second. Silicon has one known nuclear isomer , Si, with a half-life less than 210 nanoseconds. Si undergoes low-energy beta decay to P and then stable S . Si may be produced by the neutron activation of natural silicon and is thus useful for quantitative analysis; it can be easily detected by its characteristic beta decay to stable P , in which

9632-432: The mechanical behaviour of volcanic rocks can help us better understand volcanic hazards, such as flank collapse. Volcanic rocks : Subvolcanic rocks : Plutonic rocks : Picrite basalt Peridotite Basalt Diabase (Dolerite) Gabbro Andesite Microdiorite Diorite Dacite Microgranodiorite Granodiorite Rhyolite Microgranite Granite Silicon Silicon

9744-714: The moment of ejection; they may then cool to form a non-porphyritic, finely crystalline rock, or if more rapidly chilled may in large part be non-crystalline or glassy (vitreous rocks such as obsidian, tachylyte , pitchstone ). A common feature of glassy rocks is the presence of rounded bodies ( spherulites ), consisting of fine divergent fibres radiating from a center; they consist of imperfect crystals of feldspar, mixed with quartz or tridymite ; similar bodies are often produced artificially in glasses that are allowed to cool slowly. Rarely these spherulites are hollow or consist of concentric shells with spaces between ( lithophysae ). Perlitic structure, also common in glasses, consists of

9856-435: The monocrystalline silicon: 75,000 to 150,000 metric tons per year. The market for the lesser grade is growing more quickly than for monocrystalline silicon. By 2013, polycrystalline silicon production, used mostly in solar cells, was projected to reach 200,000 metric tons per year, while monocrystalline semiconductor grade silicon was expected to remain less than 50,000 tons per year. Silicon quantum dots are created through

9968-594: 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

10080-422: The ocean: chemical weathering of continental rocks, river transport, dissolution of continental terrigenous silicates, and the reaction between submarine basalts and hydrothermal fluid which release dissolved silicon. All four of these fluxes are interconnected in the ocean's biogeochemical cycle as they all were initially formed from the weathering of Earth's crust. Approximately 300–900 megatonnes of Aeolian dust

10192-641: The oceans from the Sahara and Gobi Desert, respectively. Riverine transports are the major source of silicon influx into the ocean in coastal regions, while silicon deposition in the open ocean is greatly influenced by the settling of Aeolian dust. Silicon of 96–99% purity is made by carbothermically reducing quartzite or sand with highly pure coke . The reduction is carried out in an electric arc furnace , with an excess of SiO 2 used to stop silicon carbide (SiC) from accumulating: This reaction, known as carbothermal reduction of silicon dioxide, usually

10304-490: The oceans through groundwater and riverine transport. Large fluxes of groundwater input have an isotopic composition which is distinct from riverine silicon inputs. Isotopic variations in groundwater and riverine transports contribute to variations in oceanic Si values. Currently, there are substantial differences in the isotopic values of deep water in the world's ocean basins . Between the Atlantic and Pacific oceans, there

10416-505: The oxide and isolate the element. After an attempt to isolate silicon in 1808, Sir Humphry Davy proposed the name "silicium" for silicon, from the Latin silex , silicis for flint, and adding the "-ium" ending because he believed it to be a metal. Most other languages use transliterated forms of Davy's name, sometimes adapted to local phonology (e.g. German Silizium , Turkish silisyum , Catalan silici , Armenian Սիլիցիում or Silitzioum ). A few others use instead

10528-409: The periphery. In the feldspars the center is usually richer in calcium than the surrounding layers, and successive zones may often be noted, each less calcic than those within it. Phenocrysts of quartz (and of other minerals), instead of sharp, perfect crystalline faces, may show rounded corroded surfaces, with the points blunted and irregular tongue-like projections of the matrix into the substance of

10640-454: The presence of concentric rounded cracks owing to contraction on cooling. The phenocrysts or porphyritic minerals are not only larger than those of the ground-mass; as the matrix was still liquid when they formed they were free to take perfect crystalline shapes, without interference by the pressure of adjacent crystals. They seem to have grown rapidly, as they are often filled with enclosures of glassy or finely crystalline material like that of

10752-561: The product of explosive volcanism. They are often felsic (high in silica). Pyroclastic rocks are often the result of volcanic debris, such as ash , bombs and tephra , and other volcanic ejecta . Examples of pyroclastic rocks are tuff and ignimbrite . Shallow intrusions , which possess structure similar to volcanic rather than plutonic rocks, are also considered to be volcanic, shading into subvolcanic . The terms lava stone and lava rock are more used by marketers than geologists, who would likely say "volcanic rock" (because lava

10864-576: The product to a brown powder by repeatedly washing it. As a result, he is usually given credit for the element's discovery. The same year, Berzelius became the first to prepare silicon tetrachloride ; silicon tetrafluoride had already been prepared long before in 1771 by Carl Wilhelm Scheele by dissolving silica in hydrofluoric acid . In 1823 for the first time Jacob Berzelius discovered silicon tetrachloride (SiCl 4 ). In 1846 Von Ebelman's synthesized tetraethyl orthosilicate (Si(OC 2 H 5 ) 4 ). Silicon in its more common crystalline form

10976-450: The product, nor identify it as a new element. Silicon was given its present name in 1817 by Scottish chemist Thomas Thomson . He retained part of Davy's name but added "-on" because he believed that silicon was a nonmetal similar to boron and carbon . In 1824, Jöns Jacob Berzelius prepared amorphous silicon using approximately the same method as Gay-Lussac (reducing potassium fluorosilicate with molten potassium metal), but purifying

11088-724: The production of volatile organic compounds and phytohormones which play a significant role in plant defense mechanisms. In more advanced plants, the silica phytoliths (opal phytoliths) are rigid microscopic bodies occurring in the cell. Several horticultural crops are known to protect themselves against fungal plant pathogens with silica, to such a degree that fungicide application may fail unless accompanied by sufficient silicon nutrition. Silicaceous plant defense molecules activate some phytoalexins , meaning some of them are signalling substances producing acquired immunity . When deprived, some plants will substitute with increased production of other defensive substances. Life on Earth

11200-467: 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

11312-428: The quantum dot, allowing electrons to transfer between them, filling the holes and preventing recombination. Fluorescence resonance energy transfer occurs when a complex forms between the quantum dot and a quencher molecule. The complex will continue to absorb light but when the energy is converted to the ground state it does not release a photon, quenching the material. The third method uses different approach by measuring

11424-419: The reducing agent. The spongy pieces of silicon thus produced are melted and then grown to form cylindrical single crystals, before being purified by zone refining . Other routes use the thermal decomposition of silane or tetraiodosilane ( SiI 4 ). Another process used is the reduction of sodium hexafluorosilicate , a common waste product of the phosphate fertilizer industry, by metallic sodium : this

11536-478: The resultant mechanical behaviour (e.g., Young's modulus, compressive and tensile strength, and the pressure at which they transition from brittle to ductile behaviour ). As for other crustal rocks, volcanic rocks are brittle and ductile at low and high effective confining pressures, respectively. Brittle behaviour is manifest as faults and fractures, and ductile behaviour can either be distributed (cataclastic pore collapse) or localised (compaction bands). Understanding

11648-455: The surface of the Earth. Volcanic rocks are named according to both their chemical composition and texture. Basalt is a very common volcanic rock with low silica content. Rhyolite is a volcanic rock with high silica content. Rhyolite has silica content similar to that of granite while basalt is compositionally equal to gabbro . Intermediate volcanic rocks include andesite , dacite , trachyte , and latite . Pyroclastic rocks are

11760-535: The thermal processing of hydrogen silsesquioxane into nanocrystals ranging from a few nanometers to a few microns, displaying size dependent luminescent properties. The nanocrystals display large Stokes shifts converting photons in the ultraviolet range to photons in the visible or infrared, depending on the particle size, allowing for applications in quantum dot displays and luminescent solar concentrators due to their limited self absorption. A benefit of using silicon based quantum dots over cadmium or indium

11872-477: The world's use of free silicon. Silicon is an important constituent of transformer steel , modifying its resistivity and ferromagnetic properties. The properties of silicon may be used to modify alloys with metals other than iron. "Metallurgical grade" silicon is silicon of 95–99% purity. About 55% of the world consumption of metallurgical purity silicon goes for production of aluminium-silicon alloys ( silumin alloys) for aluminium part casts , mainly for use in

11984-411: Was a silicon radio crystal detector, developed by American engineer Greenleaf Whittier Pickard in 1906. In 1940, Russell Ohl discovered the p–n junction and photovoltaic effects in silicon. In 1941, techniques for producing high-purity germanium and silicon crystals were developed for radar microwave detector crystals during World War II . In 1947, physicist William Shockley theorized

12096-453: Was going on while the mass was still creeping forward under the surface of the Earth, the latest formed minerals (in the ground-mass ) are commonly arranged in subparallel winding lines that follow the direction of movement (fluxion or fluidal structure)—and larger early minerals that previously crystallized may show the same arrangement. Most lavas fall considerably below their original temperatures before emitted. In their behavior, they present

12208-464: Was not prepared until 31 years later, by Deville . By electrolyzing a mixture of sodium chloride and aluminium chloride containing approximately 10% silicon, he was able to obtain a slightly impure allotrope of silicon in 1854. Later, more cost-effective methods have been developed to isolate several allotrope forms, the most recent being silicene in 2010. Meanwhile, research on the chemistry of silicon continued; Friedrich Wöhler discovered

12320-443: 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

12432-480: Was still liquid at the moment of eruption. At this time they were exposed only to atmospheric pressure, and the steam and other gases, which they contained in great quantity were free to escape; many important modifications arise from this, the most striking being the frequent presence of numerous steam cavities ( vesicular structure) often drawn out to elongated shapes subsequently filled up with minerals by infiltration ( amygdaloidal structure). As crystallization

12544-552: Was synthesised by Charles Friedel and James Crafts in 1863, but detailed characterisation of organosilicon chemistry was only done in the early 20th century by Frederic Kipping . Starting in the 1920s, the work of William Lawrence Bragg on X-ray crystallography elucidated the compositions of the silicates, which had previously been known from analytical chemistry but had not yet been understood, together with Linus Pauling 's development of crystal chemistry and Victor Goldschmidt 's development of geochemistry . The middle of

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