what is allotropy in chemistry
Answers
Explanation:
Allotropy or allotropism (from Ancient Greek ἄλλος (allos), meaning 'other', and τρόπος (tropos), meaning '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;[1] the atoms of the element are bonded together in a different manner. For example, the allotropes of carbon include diamond (the carbon atoms are bonded together in a tetrahedral lattice arrangement), 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 crystalline material, is polymorphism. Allotropy refers only to different forms of an element within the same phase (i.e.: solid, liquid or gas states); differences in these states alone would not constitute examples of allotropy.
For some elements, allotropes have different molecular formulae despite difference in 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 phases; for example, phosphorus has numerous solid allotropes, which all revert to the same P4 form when melted to the liquid state.
Answer:
Allotropy, the existence of a chemical element in two or more forms, which may differ in the arrangement of atoms in crystalline solids or in the occurrence of molecules that contain different numbers of atoms. The existence of different crystalline forms of an element is the same phenomenon that in the case of compounds is called polymorphism. Allotropes may be monotropic, in which case one of the forms is the most stable under all conditions, or enantiotropic, in which case different forms are stable under different conditions and undergo reversible transitions from one to another at characteristic temperatures and pressures.
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Allotropy
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Ernst Julius Cohen
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Chemical element
Polymorphism
Monotropy
Allotrope
Enantiotropy
Elements exhibiting allotropy include tin, carbon, sulfur, phosphorus, and oxygen. Tin and sulfur are enantiotropic: the former exists in a gray form, stable below 13.2° C, and a white form, stable at higher temperatures; sulfur forms rhombic crystals, stable below 95.5° C, and monoclinic crystals, stable between 95.5° C and the melting point (119° C). Carbon, phosphorus, and oxygen are monotropic; graphite is more stable than diamond, red phosphorus is more stable than white, and diatomic oxygen, having the formula O2, is more stable than triatomic oxygen (ozone, O3) under all ordinary conditions.
chemical properties of Sulfur (part of Periodic Table of the Elements imagemap)
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This allotropy, or transformat