Polymorphism (materials science)

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According to EA Mitscherlich, in materials science and mineralogy, polymorphism is the property that a substance can appear in different manifestations ( modifications ). These have the same chemical composition ( stoichiometry ), but differ in the spatial arrangement of the atoms and have different properties. Different structures may be due to influences such as pressure and / or temperature form ( solvothermal ) .

A special form of polymorphism is the polytype , which occurs in compounds that crystallize in layer lattices, such as silicon carbide or silicon nitride .

Some organic molecules such as drugs , pigments , fats or explosives can also be polymorphic in their crystalline state.



With two modifications one speaks of dimorphism, with three modifications of trimorphism. If a mirror-inverted modification occurs, it is called enantiomorphism .

When different modifications can be mutually interconverted, enantiotropy is present; if the direct conversion is only possible in one direction, monotropy .

When one and the same element occurs in different states, one speaks of allotropy , e.g. B. carbon as graphite as well as diamond .

Web links

Wiktionary: polymorphism  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Joel Bernstein: Polymorphism in Molecular Crystals , Oxford University Press 2002, ISBN 978-0-19-850605-8 .