What is Polymorphism (materials science)?
In [[materials science]], '''polymorphism''' is the ability of a solid material to exist in more than one form or [[crystal structure]]. Polymorphism can be found in any crystalline material including [[Polymer|polymers]], [[Mineral|minerals]], and [[Metal|metals]]. It is related to [[allotropy]], which refers to [[Chemical element|chemical elements]]. The complete morphology of a material is described by polymorphism and other variables such as [[crystal habit]], [[Amorphous solid|amorphous fraction]] or [[Crystallographic defect|crystallographic defects]]. Polymorphism is important in fields such as [[Pharmaceutical|pharmaceuticals]], [[Agrochemical|agrochemicals]], [[Pigment|pigments]], [[Dye|dyes]], [[Food|foods]], and [[Explosive|explosives]]. Polimorphism that exists because of a difference in crystal packing is called '''packing polymorphism'''. Polymorphism can also result from the existence of different [[Conformational isomerism|conformers]] of the same molecule in '''conformational polymorphism'''. In '''pseudopolymorphism''' the different crystal types are the result of [[Mineral hydration|hydration]] or [[solvation]]. This is more correctly referred to as '''solvomorphism''' as different solvates have different chemical formulas. An example of an organic polymorph is [[glycine]], which is able to form [[Monoclinic crystal system|monoclinic]] and [[Hexagonal crystal family|hexagonal crystals]]. [[Silica]] is known to form many polymorphs, the most important of which are; [[Quartz|α-quartz]], [[Quartz|β-quartz]], [[tridymite]], [[cristobalite]], [[moganite]], [[coesite]], and [[stishovite]]. A classical example is the pair of minerals, [[calcite]] and [[aragonite]], both forms of [[calcium carbonate]]. An analogous phenomenon for [[amorphous]] materials is [[polyamorphism]], when a substance can take on several different amorphous modifications. [[Category:Materials science]]