![]() ![]() Jöns Jacob Berzelius discovered the silicon element in 1823. Natural silicate compounds were also used in various types of mortar for construction of early human dwellings. Glass containing silica was manufactured by the Egyptians since at least 1500 BC, as well as by the ancient Phoenicians. 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. Owing to the abundance of silicon in the Earth's crust, natural silicon-based materials have been used for thousands of years. Silica is deposited in many plant tissues. Only traces are required by most animals, but some sea sponges and microorganisms, such as diatoms and radiolaria, secrete skeletal structures made of silica. Silicon is an essential element in biology. 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. The small portion of very highly purified elemental silicon used in semiconductor electronics (<10% ) is essential to the transistors and integrated circuit chips used in most modern technology such as smartphones and other computers. 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. Silicon is the basis of the widely used synthetic polymers called silicones. ![]() Silicon compounds such as silicon carbide are used as abrasives and components of high-strength ceramics. They are also used in whiteware ceramics such as porcelain, and in traditional silicate-based soda-lime glass and many other specialty glasses. 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. Such use includes industrial construction with clays, silica sand, and stone. Most silicon is used commercially without being separated, often with very little processing of the natural minerals. 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. It is widely distributed in space in cosmic dusts, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. 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. Its melting and boiling points of 1414 ☌ and 3265 ☌, respectively, are the second highest among all the metalloids and nonmetals, being surpassed only by boron. Its oxides form a family of anions known as silicates. It is relatively unreactive.īecause 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. 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 a hard, brittle crystalline solid with a blue-grey metallic luster, and is a tetravalent metalloid and semiconductor. ![]() Compared to organic defoamers, silicone antifoam compounds are more effective and so require very low dosage levels because silicone oils have lower surface tensions and so spread better across the liquid-air interfaces.Silicon is a chemical element with the symbol Si and atomic number 14. The defoaming is triggered when an oil/silica droplet merges into the air-water interface, when the oil spreads across the liquid-air interface, which is destabilized (the bubble bursts) by the ‘pin pricks’ provided by the silica. The challenge is that the silica must be partly, but not completely, hydrophobic. Silica plays a key role in the formulation, to achieve exactly the antifoaming level required. The composition of the silicone compound has a determining influence on its performance and utility. Silica particles are dispersed in the silicone oil to form the silicone compound. Within the silicone oils themselves, the chains glide and slip over one another, so the oils are fluid. ![]() Each silicon atom is bonded to two carbon-based substitution groups, almost invariably methyl groups. The backbone structure of silicone oils is made up of a chain of alternating silicon and oxygen atoms. ![]()
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