The AM-4 Family of Layered Titanosilicates: Single-Crystal-to-Single-Crystal Transformation, Synthesis and Ionic Conductivity

Abstract

Flexible crystal(水晶) structures, which exhibit(展览) single-crystal(水晶)-to-single-crystal(水晶) (SCSC) transformations(转型), are attracting attention(注意) in many applied aspects: magnetic(磁) switches, catalysis, ferroelectrics and sorption. Acid treatment(治疗) for titanosilicate material(材料) AM-4 and natural(自然) compounds with the same structures led to SCSC transformation(转型) by loss(损失) Na+, Li+ and Zn2+ cations with large structural(结构) changes (20% of the unit(单位)-cell(细胞) volume(体积)). The conservation(保育) of crystallinity through complex(复杂) transformation(转型) is possible due(由于) to the formation(形成) of a strong hydrogen bonding(债券) system(系统). The mechanism(机制) of transformation(转型) has been characterized using single-crystal(水晶) X-ray(射线) diffraction analysis(分析), powder(粉) diffraction, Rietvield refinement, Raman spectroscopy and electron microscopy. The low migration(迁移) energy(能源) of cations in the considered materials(材料) is confirmed using bond(债券)-valence and density(密度) functional(功能) theory(理论) calculations, and the ion conductivity of the AM-4 family’s materials(材料) has been experimentally verified.

Migration paths of the Na+-ion diffusion for minerals of the lovozerite group: crystallochemical and DFT modeling

“…In these structures, some channels have radius in the range of 1.90-1.95 Å that possibly will expand slightly at pressure or high temperature. 50 Imandrite, koashvite and lovozerite have a migration map in the form of chains along the [001] direction. The most branched and wide system of channels (3D migration map) for the Na + -ion diffusion in this group of minerals has the structures of combeite, kapustinite, kazakovite (Fig.…”