Property of some chemical elements to exist in two or more different forms
Not to be confused with Allotrophy.
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 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 element are bonded together in different manners.[1]
For example, the allotropes of carbon include diamond (the carbon atoms are bonded together to form a cubic lattice of tetrahedra), graphite (the carbon atoms are bonded together in sheets of a hexagonal lattice), graphene (single sheets of graphite), and fullerenes (the carbon atoms are bonded together in spherical, tubular, or ellipsoidal formations).
The term allotropy is used for elements only, not for compounds. The more general term, used for any compound, is polymorphism, although its use is usually restricted to solid materials such as crystals. Allotropy refers only to different forms of an element within the same physical phase (the state of matter, such as a solid, liquid or gas). The differences between these states of matter would not alone constitute examples of allotropy. Allotropes of chemical elements are frequently referred to as polymorphs or as phases of the element.
For some elements, allotropes have different molecular formulae or different crystalline structures, as well as a difference in physical phase; for example, two allotropes of oxygen (dioxygen, O2, and ozone, O3) can both exist in the solid, liquid and gaseous states. Other elements do not maintain distinct allotropes in different physical phases; for example, phosphorus has numerous solid allotropes, which all revert to the same P4 form when melted to the liquid state.
^IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version: (2006–) "Allotrope". doi:10.1351/goldbook.A00243
Allotropy or allotropism (from Ancient Greek ἄλλος (allos) 'other', and τρόπος (tropos) 'manner, form') is the property of some chemical elements to exist...
form polycrystals. For pure chemical elements, polymorphism is known as allotropy. For example, diamond and graphite are two crystalline forms of carbon...
(dynamic isomerization) leads to chemical change, not polymorphism. As well, allotropy of elements and polymorphism have been linked historically. However, allotropes...
known as the Curie temperature. Crystal system Daintith, John (2008). "allotropy". A Dictionary of Chemistry (6th ed.). Oxford University Press. ISBN 9780199204632...
structure without changing its chemical makeup. In elements, this is known as allotropy, whereas in compounds it is known as polymorphism. The change from one...
variables such as pressure and temperature. Polymorphism is related to allotropy, which refers to elemental solids. The complete morphology of a material...
GH (2010). "Carbene Stabilization of Diarsenic: From Hypervalency to Allotropy". Chemistry: A European Journal. 16 (2): 432–5. doi:10.1002/chem.200902840...
iron-carbon alloy known as steel, undergoes a change in the arrangement (allotropy) of the atoms of its crystal matrix at a certain temperature (usually...
on conditions like temperature and pressure. This rearrangement called allotropy or polymorphism, may occur several times, at many different temperatures...
H. (2010). "Carbene Stabilization of Diarsenic: From Hypervalency to Allotropy". Chemistry: A European Journal. 16 (2): 432–5. doi:10.1002/chem.200902840...
ability of an element to exist in one of many structural forms is known as 'allotropy'. The reference state of an element is defined by convention, usually...
persecution Cause of death Ernst Cohen 1869–1944 Dutch chemist, work on the allotropy of metals Jewish gas chamber at Auschwitz Elisabeth Wollman 1888–1943...
, as reviewed by David Young; as Young notes, "The literature on the allotropy of sulfur presents the most complex and confused situation of all the...
by drainage from the surrounding land. allotropic relating to or characterized by allotropy. Also, ALLOTROPHIC. allotropy Chemistry, the property ..."...
combine with oxygen in reactions. He also introduced the possibility of allotropy in chemical elements when he discovered that diamond is a crystalline...
– 6 March 1944) was a Dutch Jewish chemist known for his work on the allotropy of metals. Cohen studied chemistry under Svante Arrhenius in Stockholm...
(other; is an element in words such as allogamy, allomorph, allopathy, allotropy), Latin alius (other), alter (another, the other one, second), French...
biochemist Ernst Cohen, Dutch Jewish chemist known for his work on the allotropy of metals Ernst Gebauer, German painter Ernst Haeckel, German biologist...
Nuclear 2013 Zalutsky & Pruszynski 2011, p. 181 Addison WE 1964, The Allotropy of the Elements, Oldbourne Press, London Addison CC & Sowerby DB 1972...
even at −31 °C. Polyiodide Halogen bond Inorganic polymer Catenation Allotropy King, R. Bruce (2005). "Chlorine, Bromine, Iodine, & Astatine: Inorganic...
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