page_title: Nonmetal
section_title: Applications in common
hierarchical_section_title: Nonmetal / Applications in common
caption_attribution_description: English: A 3 phase 115 kV 1200 A circuit breaker, SF 6 type, mounted outdoors at the substation near the Manitoba Hydro Slave Falls generating station. Current enters and leaves the breaker through the bare wire leads terminating on the top of the insulator bushings. The horizontal cylindrical tanks contain the interrupters which operate in an envelope filled with sulfur hexafluoride (SF6) gas. The control cabinet for the breaker is on the left side of the unit, which contains the mechanism that opens and closes all three poles at the same time. Unlike smaller breakers used in low voltage systems, the over current sensing relays are always separately mounted in this form of breaker. Part of the steel lattice structure of the station can be seen, as well as part of another breaker at the left side of the picture. Picture taken from en:Circuit breaker.
context_page_description: In chemistry, a nonmetal is a chemical element that mostly lacks the characteristics of a metal. Physically, a nonmetal tends to have a relatively low melting point, boiling point, and density. A nonmetal is typically brittle when solid and usually has poor thermal conductivity and electrical conductivity. Chemically, nonmetals tend to have relatively high ionization energy, electron affinity, and electronegativity. They gain or share electrons when they react with other elements and chemical compounds. Seventeen elements are generally classified as nonmetals: most are gases; one is a liquid; and a few are solids. Metalloids such as boron, silicon, and germanium are sometimes counted as nonmetals.
  The nonmetals are divided into two categories reflecting their relative propensity to form chemical compounds: reactive nonmetals and noble gases. The reactive nonmetals vary in their nonmetallic character. The less electronegative of them, such as carbon and sulfur, mostly have weak to moderately strong nonmetallic properties and tend to form covalent compounds with metals.
context_section_description: Nonmetals do not have any universal or near-universal applications. This is not the case with metals, most of which have structural uses; nor the metalloids, the typical uses of which extend to (for example) oxide glasses, alloying components, and semiconductors.
  Shared applications of different subsets of the nonmetals instead encompass their presence in, or specific uses in the fields of cryogenics and refrigerants: H, He, N, O, F and Ne; fertilisers: H, N, P, S, Cl (as a micronutrient) and Se; household accoutrements: H (primary constituent of water), He (party balloons), C (in pencils, as graphite), N (beer widgets), O (as peroxide, in detergents), F (as fluoride, in toothpaste), Ne (lighting), P (matches), S (garden treatments), Cl (bleach constituent), Ar (insulated windows), Se (glass; solar cells), Br (as bromide, for purification of spa water), Kr (energy saving fluorescent lamps), I (in antiseptic solutions), Xe (in plasma TV display cells, a technology subsequently made redundant by low cost OLED displays), while Rn also sometimes occurs, but then as an unwanted, potentially hazardous indoor pollutant; industrial acids: C, N, F, P, S and Cl; inert air replacements: N, Ne, S (in sulfur hexafluoride SF₆), Ar, Kr and Xe; lasers and lighting: He, C (in carbon dioxide lasers, CO₂), N, O (in a chemical oxygen iodine laser), F (in a hydrogen fluoride laser, HF), Ne, S (in a sulfur lamp), Ar, Kr and Xe; and medicine and pharmaceuticals: He, O, F, Cl, Br, I, Xe and Rn.
  The number of compounds formed by nonmetals is vast. The first nine places in a "top 20" table of elements most frequently encountered in 8,427,300 compounds, as listed in the Chemical Abstracts Service register for July 1987, were occupied by nonmetals. Hydrogen, carbon, oxygen and nitrogen were found in the majority (greater than 64 per cent) of compounds. Silicon, a metalloid, was in 10th place. The highest rated metal, with an occurrence frequency of 2.3 per cent, was iron, in 11th place.
caption: A high-voltage circuit-breaker employing sulfur hexafluoride SF6 as its inert (air replacement) interrupting medium[74]
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