钙钛矿结构[Perovskite Structure] - 达人(其实～我是卧底，来自外星)

2005/07/19 | 钙钛矿结构[Perovskite Structure]
类别(℃〖化学〗) | 评论(0) | 阅读(266) | 发表于 20:09: A structure consisting of 12-coordinated A⁺² atoms on the corners of a cube, octahedral O ions on the faces, and tetrahedral B⁺⁴ ions in the center. The name comes from the mineral CaTiO₃ which exhibits this structure. The structure is capable of incorporating a large number of rare ores such as Ta and Nb. They are rare, but are found in Tanzania, Brazil, and Canada. Perovskite structures have the curious property that the central atom does not "touch" its coordination neighbors, in violation of Pauling's rules. This gives the structure the strange property of ferroelectricity. Olivine and garnet have this structure. In fact, all common silicates structures transform to perovskite at the high pressures in the Earth 's interior. Possibly related to the structure's strange ferroelectricity is that many superconductors have the perovskite structure.; 0