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Allotropy (Gr. allos, other, and tropos, manner), a name applied by Jons Jacob Berzelius to the property possessed by certain
substances of existing in different modifications; the various forms are known as allotropes. Jons Jacob Berzelius used the name in an entirely
different sense (see Macmillan Encyclopedia of Chemistry, edited by
J.J.Lagowski, 1997, Simon Schuster).
Some classic examples of elements that have allotropes are phosphorus (in "red" and "white" and "purple" etc. forms) and carbon (in the form of graphite, diamond, fullerenes, and others - see allotropes of carbon). The term allotropes may also be used to refer to the molecular forms of an element (such as a diatomic gas), even if there is only one such additional form.
Allotropy specifically refers to the chemical bond structure between atoms of the same kind and should not be confused with the existence of multiple physical states, such as with water, which can exist as a gas ( steam), a liquid (water), or a solid ( ice). These phases of water are not allotropes, since they are caused by changes in the physical bonding between water molecules, rather than changes in the chemical bonding of the water molecules themselves. Allotropes of an element can be in any state, gaseous, liquid, or solid.
Allotropy usually refers to pure elemental solids, while polymorphism may refer to elemental solids or more generally to any material having multiple crystal structures.
As can be seen with the example of carbon allotropes, certain physical properties can vary dramatically from allotrope to allotrope. In diamond, carbon atomFor alternative meanings see atom (disambiguation). An atom is a microscopic structure found in all ordinary matter around us. Atoms are composed of 3 types of subatomic particles: electrons, which have a negative charge; protons, which have a positive chs are connected each to four other carbon atoms in a tetrahedalA tetrahedron (plural: tetrahedra is a polyhedron composed of four triangular faces, three of which meet at each vertex. A regular tetrahedron is one in which the four triangles are regular, or "equilateral," and is one of the Platonic solids. The area A lattice structure, whereas in graphite, each carbon atom is firmly bonded to just three other carbon atoms in hexagonA regular hexagon A hexagon (also known as "sexagon") is a polygon with six edges and six vertices. Its Schlafli symbol is {6}. The internal angles of a regular hexagon (one where all sides and all angles are equal) are all 120 °. Like squares and equilatal sheets. These hexagonal sheets are then more loosely coupled to one another in stacks. The structure of fullerenes (a carbon allotrope found in sootSoot also called lampblack or carbon black is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys and other surfaces exposed to smoke—especially from the combustion of carbon-rich org) resembles that of graphite, except that instead of hexagons of carbon atoms, smaller regular polygonA polygon (from the Greek poly for "many", and gonos for "angle") is a closed planar path composed of a finite number of sequential straight line segments. The straight line segments that make up the polygon are called its sides or edges and the points whs are formed, such as a mix of hexagons and pentagonThis is an article about the geometrical shape. See The Pentagon for an article about the building near Washington, DC. See also: Pentagon (disambiguation). In geometry, a pentagon is any five-sided polygon. However, the term is commonly used to mean a res, such that the sheet can fold back onto itself into closed spheroidA spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. If the ellipse is rotated about its major axis, the surface is called a prolate spheroid (similar to the shape of a rugby ball). If the mis, as with the seams of a soccer ball.
Allotropes not only show dramatic differences in physical properties but also
show differences in chemical properties. Graphite can be oxidized by nitric acid to give compounds related to benzene whereas diamond does not give
compounds related to benzene.
Chemistry
