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Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other' and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of the elements. Allotropes are different structural modifications of an element: the atoms of the ...
Carbon is capable of forming many allotropes (structurally different forms of the same element) due to its valency (tetravalent). Well-known forms of carbon include diamond and graphite. In recent decades, many more allotropes have been discovered and researched, including ball shapes such as buckminsterfullerene and sheets such as graphene.
In elements, this is known as allotropy, whereas in compounds it is known as polymorphism. The change from one crystal structure to another, from a crystalline solid to an amorphous solid, or from one amorphous structure to another (polyamorphs) are all examples of solid to solid phase transitions.
Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. At standard temperature and pressure, two atoms of the element bond to form N 2, a colorless and odorless diatomic gas.
White phosphorus (left), red phosphorus (center left and center right), and violet phosphorus (right) White phosphorus and resulting allotropes. Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and ...
Biological roles of the elements. A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]
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 ...
Technology portal. v. t. e. A fullerene is an allotrope of carbon whose molecules consist of carbon atoms connected by single and double bonds so as to form a closed or partially closed mesh, with fused rings of five to seven atoms. The molecules may have hollow sphere - and ellipsoid -like forms, tubes, or other shapes.