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Allotropy. Property of some chemical elements to exist in two or more different forms. Diamond and graphite are two allotropes of carbon: pure forms of the same element that differ in crystalline structure. Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some ...
Elements including metals may exhibit polymorphism. Allotropy is the term used when describing elements having different forms and is used commonly in the field of metallurgy. Some (but not all) allotropes are also polymorphs. For example, iron has three allotropes that are also polymorphs. Alpha-iron, which exists at room temperature, has a ...
Graphite. Graphite, named by Abraham Gottlob Werner in 1789, from the Greek γράφειν (graphein, "to draw/write", for its use in pencils) is one of the most common allotropes of carbon. Unlike diamond, graphite is an electrical conductor. Thus, it can be used in, for instance, electrical arc lamp electrodes.
The alpha iron (α-Fe) is a body-centered cubic (BCC) and the gamma iron (γ-Fe) is a face-centered cubic (FCC). At atmospheric pressure, three allotropic forms of iron exist, depending on temperature: alpha iron (α-Fe, ferrite), gamma iron (γ-Fe, austenite), and delta iron (δ-Fe). At very high pressure, a fourth form exists, epsilon iron ...
Allotropes of sulfur. Cyclo -octasulfur (cyclo - S8 or cyclooctasulfane), the most prevalent allotrope of sulfur in nature. The element sulfur exists as many allotropes. In number of allotropes, sulfur is second only to carbon. [1] In addition to the allotropes, each allotrope often exists in polymorphs (different crystal structures of the same ...
Crystal structure of table salt (sodium in purple, chlorine in green) In crystallography, crystal structure is a description of ordered arrangement of atoms, ions, or molecules in a crystalline material. [1] Ordered structures occur from intrinsic nature of constituent particles to form symmetric patterns that repeat along the principal ...
Transition temperature. In crystallography, the transition temperature is the temperature at which a material changes from one crystal state (allotrope) to another. [1] More formally, it is the temperature at which two crystalline forms of a substance can co-exist in equilibrium.
On rare occasions, P 4 O 7, P 4 O 8, and P 4 O 9 are also formed, but in small amounts. This combustion gives phosphorus(V) oxide, which consists of P 4 O 10 tetrahedral with oxygen inserted between the phosphorus atoms and at their vertices: P 4 + 5 O 2 → P 4 O 10. The odour of combustion of this form has a characteristic garlic smell.