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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.
A sponge-like porous form of silicon (p-Si) is typically prepared by the electrochemical etching of silicon wafers in a hydrofluoric acid solution. [152] Flakes of p-Si sometimes appear red; [153] it has a band gap of 1.97–2.1 eV. [154] The many tiny pores in porous silicon give it an enormous internal surface area, up to 1,000 m 2 /cm 3. [155]
As a metalloid the chemistry of silicon is largely covalent in nature, noting it can form alloys with metals such as iron and copper. The common oxide of silicon (SiO 2) is weakly acidic. Germanium. Germanium is a shiny, mostly unreactive grey-white solid with a density of 5.323 g/cm 3 (about two-thirds that of iron), and is hard (MH 6.0) and ...
A compound semiconductor is a semiconductor compound composed of chemical elements of at least two different species. These semiconductors form for example in periodic table groups 13–15 (old groups III–V), for example of elements from the Boron group (old group III, boron, aluminium, gallium, indium) and from group 15 (old group V, nitrogen, phosphorus, arsenic, antimony, bismuth).
e. In the context of the periodic table a nonmetal is a chemical element that mostly lacks distinctive metallic properties. They range from colorless gases like hydrogen to shiny crystals like iodine. Physically, they are usually lighter (less dense) than elements that form metals and are often poor conductors of heat and electricity.
Appearance. Silicon compounds are compounds containing the element silicon (Si). As a carbon group element, silicon often forms compounds in the +4 oxidation state, though many unusual compounds have been discovered that differ from expectations based on its valence electrons, including the silicides and some silanes.
Silica cycle. Silicon cycle and balance in the modern world ocean [1] Input, output, and biological silicon fluxes, with possible balance. Total silicon inputs = total silicon outputs = 15.6 Tmol Si yr −1 in reasonable agreement with the individual range of each flux. White arrows represent fluxes of net sources of dissolved silicic acid and ...
Silicon carbide (SiC), also known as carborundum (/ ˌ k ɑːr b ə ˈ r ʌ n d əm /), is a hard chemical compound containing silicon and carbon. A wide bandgap semiconductor , it occurs in nature as the extremely rare mineral moissanite , but has been mass-produced as a powder and crystal since 1893 for use as an abrasive .