![]() The melting point of the crystalline allotrope is about 2,570 ☏ (1,410 ☌), its boiling point is about 4,270 ☏ (2,355 ☌), and its density is 1.35 ounces per cubic inch (2.33 grams per cubic centimeter). The other allotrope is an amorphous brown powder. Silicon exists in two allotropic forms, one of which consists of shiny, grayish black needle-like or crystal plates. The crustal composition is three-quarters oxygen and silicon. By about 3.5 billion years ago, the outermost layer had cooled to a crustal surface. While still molten lighter atoms -including silicon and oxygen (atomic weights 28 and 16), moved outward from the core region, while the heavier iron atoms ( atomic weight 56) dominated the central core. In rough terms, the Earth is essentially a spheroid of iron (the core) surrounded by layers (the mantle and the crust) of silicon and oxygen dominated compounds that include the other elements.Įarth was originally a molten ball of mostly iron, oxygen, silicon and aluminum that cooled. In terms of weight, silicon is the second most abundant element in the crust of Earth at 27.7% - second only to oxygen (46.6%). The conductive properties of silicon allow micro-devices to perform millions of calculations per second. Silicon, is a key component of microchips and microprocessors that allow the construction of inexpensive digital wristwatch to worldwide networks of computers. Silicon consists of three stable isotopes of mass numbers 28, 29 and 30. It exists also in two amorphous (shapeless) forms, a brown powder and a black crystal. In its crystalline form of dark gray crystals, it has a specific gravity of 2.42 at 68 ☏ (20 ☌), a melting point of 2,588 ☏ (1,420 ☌) and a boiling point 5,936 ☏ (3,280 ☌). The seventh most abundant element in the universe, silicon is the second element in Group 14 of the periodic table. In a word, please contact Alfa Chemistry if you are interested in the organosilicon compounds.Silicon is the chemical element of atomic number 14, symbol Si and atomic weight 28.085. This reaction showed good scope and functional group tolerance, affording series of target diynes, enynes, arylacetylenes, alkenylarenes, biaryls and allylarenes and so on. In addition, they also used in organic reactions for the pharmaceutical industry as auxiliary materials and protecting groups, or as protective agents for buildings.įor examples, in the presence of a palladium catalyst and a Lewis base activator such as a fluoride or hydroxyl ion, organosilicon compounds can react with a wide variety of organic electrophiles to produce the corresponding coupled products. They show different properties, for using as precursors for silicon carbide and silicon nitride coatings by chemical vapor deposition, or as catalyst components in olefin polymerization. Organosilicon compounds are also widely used in many important fields apart from silicone chemistry, such as materials science and in metallurgy. In addition, from their structure, polymeric silicones are also economic products because organosilicon units are linked by Si-O-Si bonds.įigure 1 the application of organosilicon compounds Application Thus silicone production becomes the largest consumer of monomeric silanes. The hydrolysis or methanolysis of monomeric organohalosilanes followed by polycondensation can obtain the polymeric silicones. Generally they can be divided into two categories, polymers and monomeric compounds. They are weak nucleophiles compared with other organometallic compounds because the carbon-silicon bond in organosilicon compounds is only weakly polarized. Organosilicon compounds are key organometallic compounds containing at least one silicon-carbon bond. The study of the stereochemistry of organic silicon compounds always carried out by observations of stereochemical differences rather than similarities between analogous molecules containing silicon or carbon. However, silicon is more reminiscent of its heavier congeners due to lack of stability of its multiple bonds and the limited propensity to expand its coordination sphere to five or even six. They have lower energetic barriers to distortion compared to the carbon analogues because of the bigger atomic radius. Like carbon, silicon atoms are generally four-coordinate when compounds are formed. Alfa Chemistry can offer a range of competitive organosilicon compounds with high quality.
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