{"id":27724,"date":"2020-10-21T07:29:20","date_gmt":"2020-10-21T07:29:20","guid":{"rendered":"http:\/\/sitepourvtc.com\/?page_id=27724"},"modified":"2023-08-05T07:57:19","modified_gmt":"2023-08-05T07:57:19","slug":"polymorphism-and-allotropy","status":"publish","type":"page","link":"https:\/\/sitepourvtc.com\/nuclear-engineering\/materials-science\/crystal-structures\/polymorphism-and-allotropy\/","title":{"rendered":"Polymorphism and Allotropy"},"content":{"rendered":"
A crystalline material<\/strong> is one in which the atoms are situated in a repeating or periodic array over large atomic distances. That is, long-range order exists. Upon solidification, the atoms will position themselves in a repetitive three-dimensional pattern, in which each atom is bonded to its nearest neighbor atoms. Not all solids are single crystals. For example, when liquid water starts freezing, the phase change begins with small ice crystals that grow until they fuse, forming a polycrystalline structure. In the final block of ice, each of the small crystals (called “grains<\/strong>“) is a true crystal with a periodic arrangement of atoms. Still, the whole polycrystal does not have a periodic arrangement of atoms because the periodic pattern is broken at the grain boundaries<\/strong>.<\/p>\nPolymorphism and Allotropy<\/h2>\n