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New borates with similar structures and different properties – acentric nonlinear optical KGd[B6O10(OH)2] and centrosymmetric KHo[B6O10(OH)2]тезисы доклада
- Авторы: Anastasiia Topnikova, Elena Belokoneva, Olga Dimitrova, Anatoliy Volkov, Sergey Stefanovich
- Сборник: Acta Crystallographica (31th European Crystallographic Meeting, Book of abstracts)
- Серия: A
- Том: 74
- Тезисы
- Год издания: 2018
- Место издания: Blackwell Publishing Inc UK
- Первая страница: e234
- Аннотация: Single crystals of two new borates, KGd[B6O10(OH)2] and KHo[B6O10(OH)2], have been synthesized in multi-components hydrothermal solutions at controlled pH. Similar in unit cell, the structures differ in relation to the symmetry: K,Gd-structure is solved in acentric space group P-62m, while K,Ho-structure is centrosymmetric, P-31m. Polyborate anionic layers of new type from tetrahedra and triangles are identical; however multiplication of the layers by symmetry is differently produced either by mirror plane or the inversion center. The layers of oxygen-boron tetrahedra and triangles in K,Gd- and K,Ho-borates are connected by GdO6 prisms and HoO6 octahedra, correspondingly. Second-order nonlinearity is clearly manifested by intensive SHG effect in K,Gd-borate, and absent in K,Ho-borate. K- and B-triangles positions are statistically occupied in both structures. It is noticed that an ordered model of K,Gd-structure is possible with the unit cell tripled along c-axis, symmetry P31 and polar orientation of the B-triangles.
- Добавил в систему: Топникова Анастасия Павловна