allotropy

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allotropy

(əlŏ`trəpē) [Gr.,=other form]. A chemical element is said to exhibit allotropy when it occurs in two or more forms in the same physical state; the forms are called allotropes. Allotropes generally differ in physical properties such as color and hardness; they may also differ in molecular structure or chemical activity, but are usually alike in most chemical properties. Diamond and graphite are two allotropes of the element carboncarbon
[Lat.,=charcoal], nonmetallic chemical element; symbol C; at. no. 6; interval in which at. wt. ranges 12.0096–12.0116; m.p. about 3,550°C;; graphite sublimes about 3,375°C;; b.p. 4,827°C;; sp. gr. 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.
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. Ozoneozone
, an allotropic form of the chemical element oxygen (see allotropy). Pure ozone is an unstable, faintly bluish gas with a characteristic fresh, penetrating odor. The gas has a density of 2.144 grams per liter at STP.
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 is a chemically active triatomic allotrope of the element oxygenoxygen,
gaseous chemical element; symbol O; at. no. 8; interval in which at. wt. ranges 15.99903–15.99977; m.p. −218.4°C;; b.p. −182.962°C;; density 1.429 grams per liter at STP; valence −2.
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. Phosphorusphosphorus
[Gr.,=light-bearing], nonmetallic chemical element; symbol P; at. no. 15; at. wt. 30.97376; m.p. 44.1°C;; b.p. about 280°C;; sp. gr. 1.82 at 20°C;; valence −3, +3, or +5.
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, sulfursulfur
or sulphur
, nonmetallic chemical element; symbol S; at. no. 16; interval in which at. wt. ranges 32.059–32.076; m.p. 112.8°C; (rhombic), 119.0°C; (monoclinic), about 120°C; (amorphous); b.p. 444.674°C;; sp. gr. at 20°C;, 2.07 (rhombic), 1.
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, and tintin,
metallic chemical element; symbol Sn [Lat. stannum]; at. no. 50; at. wt. 118.710; m.p. 231.9681°C;; b.p. 2,270°C;; sp. gr. 5.75 (gray), 7.3 (white); valence +2 or +4. Tin exhibits allotropy; above 13.
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 also exhibit allotropy. Many metals have allotropic crystalline forms that are stable at different temperatures. Polymorphismpolymorphism,
of minerals, property of crystallizing in two or more distinct forms. Calcium carbonate is dimorphous (two forms), crystallizing as calcite or aragonite. Titanium dioxide is trimorphous; its three forms are brookite, anatase (or octahedrite), and rutile.
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 is an analogous phenomenon observed in chemical compounds.

allotropy

[ə′lä·trə·pē]
(chemistry)
The assumption by an element of two or more different forms or structures which are most frequently stable in different temperature ranges, such as different crystalline forms of carbon as charcoal, graphite, or diamond. Also known as allotriomorphism; allotropism.

allotropy

, allotropism
the existence of an element in two or more physical forms. The most common elements having this property are carbon, sulphur, and phosphorus
References in periodicals archive ?
The study showed also the importance of considering the allotropic forms in a concise aims for characterization and treatment estimation.
My reference to Lawrence's allotropic self goes to the crux of this issue since it is one of Miller's bases for comparison and difference.
Later, in 1854, a French chemist named Henri Sainte-Claire Deville was the first to prepare crystalline silicon which is the second allotropic form of the element.
Love and hate seem but two allotropic emotions, both expressions of man's lack of fulfillment and happiness.
Elemental selenium lias been known to exist in various allotropic forms, as res amorphous form, black vitreous form, three [[alpha], [beta], [gamma]) of red crystalline monoclinic forms and grey/ black crystalline hexagonal [also referred to as trigonal] form which is also the most stable form, and some more allotropes are being discovered [51-59].