22:57 Dec 6, 2006 |
Portuguese to English translations [Non-PRO] Science - Science (general) | |||||
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| Selected response from: Maria Luisa Duarte Spain Local time: 21:54 | ||||
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5 +6 | silicon /silicone |
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silicon /silicone Explanation: chemical element:atomic number 14 an organosilicon oxide polymer with properties varying according to the organic group(s)it contains in general,silicones are characterised by chemical inertness,water-repellency,considerable thermal stability,and excellent dielectric properties -------------------------------------------------- Note added at 10 mins (2006-12-06 23:08:00 GMT) -------------------------------------------------- Silicon (IPA: /ˈsɪlikən/, Latin: silicium) is the chemical element in the periodic table that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. It is the second most abundant element in the Earth's crust, making up 25.7% of it by mass. It does not occur free in nature. It mainly occurs in minerals consisting of (practically) pure silicon dioxide in different crystalline forms (quartz, chalcedony, opal) and as silicates (various minerals containing silicon, oxygen and one or another metal), for example feldspar. These minerals occur in clay, sand and various types of rock like granite and sandstone. Silicon is the principal component of most semiconductor devices and, in the form of silica and silicates, in glass, cement, and ceramics. It is also a component of silicones, a name for various plastic substances often confused with silicon itself. Silicon is widely used in semiconductors because it remains a semiconductor at higher temperatures than the semiconductor Germanium and because its native oxide is easily grown in a furnace and forms a better semiconductor/dielectric interface than almost all other material combinations. http://en.wikipedia.org/wiki/Silicon Silicone From Wikipedia, the free encyclopedia Jump to: navigation, search Not to be confused with Silicon. Silicone caulking can be used as a basic sealant against water and air penetration.Silicones, or polysiloxanes, are inorganic-organic polymers with the chemical formula [R2SiO]n, where R = organic groups such as methyl, ethyl, and phenyl. These materials consist of an inorganic silicon-oxygen backbone (...-Si-O-Si-O-Si-O-...) with organic side groups attached to the silicon atoms, which are four-coordinate. In some cases organic side groups can be used to link two or more of these -Si-O- backbones together. By varying the -Si-O- chain lengths, side groups, and crosslinking, silicones can be synthesized with a wide variety of properties and compositions. They can vary in consistency from liquid to gel to rubber to hard plastic. The most common type is linear polydimethylsiloxane or PDMS. The second largest group of silicone materials is based on silicone resins, which are formed by branched and cage-like oligosiloxanes http://en.wikipedia.org/wiki/Silicone |
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