Three novel alkali metal fluoroaluminophosphates, Li₃[AlP₂O₇F(OH)](H₂O)_0.5 and A[Al₂(PO₄)₂F(H₂O)](A = K, Rb), were designed and synthesized by using low-temperature flux methods. They crystallized in polar space groups P₄ and P2₁2₁2₁, respectively. Li₃[AlP₂O₇F(OH)](H₂O)_0.5 features a unique two-dimensional layered structure of fluoroaluminophosphate [AlP₂O₇F(OH)]^3–_n, composed of alternately connected AlFO₅ octahedra and PO₄ tetrahedra. In contrast, with counter cations from Li⁺ to K⁺/Rb⁺, two new crystals of A[Al₂(PO₄)₂F(H₂O)](A = K, Rb) have been obtained. They possess a distinct three-dimensional anionic framework, [Al₂(PO₄)₂F]⁻_n, consisting of corner-sharing AlO₅ triangular bipyramids, AlFO₅ octahedra, and PO₄ tetrahedra, revealing intersecting open tunnels along the [010], [001], and [111] directions. Notably, both Li₃[AlP₂O₇F(OH)](H₂O)_0.5 and K[Al₂(PO₄)₂F(H₂O)] exhibit moderate second harmonic generation effects. Besides, porous material of K[Al₂(PO₄)₂F(H₂O)] exhibited remarkable ionic exchange properties with Cs⁺, implying its potential utility in the remediation of radioactive waste and offering a promising solution for managing nuclear contaminants. This research reports on their syntheses, topological structures, elemental analysis, thermal stability, IR Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy, ion exchange property, and nonlinear optical characteristics.

中文翻译：

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Li3[AlP2O7F（OH）]（H2O）0.5 和 A[Al2（PO4）2F（H2O）]（A = K， Rb）：衍生的三种极性碱性金属氟铝磷酸盐的逆阳离子模板


采用低温熔剂法设计合成了三种新型碱金属氟铝磷酸盐Li₃[AlP₂O₇F（OH）]（H₂O）_0.5和A[Al₂（PO₄）₂F（H₂O）]（A = K， Rb）。它们分别在极空间群 P₄ 和 P2₁2₁2₁ 中结晶。Li₃[AlP₂O₇F（OH）]（H₂O）_0.5 具有氟铝磷酸盐 [AlP₂O₇F（OH）]^3–_n 独特的二维层状结构，由交替连接的 AlFO₅ 八面体和 PO₄ 四面体组成。相反，通过从 Li⁺ 到 K⁺/Rb⁺ 的对阳离子，获得了 A[Al₂（PO₄）₂F（H₂O）]（A = K， Rb） 的两个新晶体。它们具有独特的三维阴离子框架 [Al₂（PO₄）₂F]⁻_n，由角共享的 AlO₅ 三角形双锥体、AlFO₅ 八面体和 PO₄ 四面体组成，揭示了沿 [010]、[001] 和 [111] 方向相交的开放隧道。值得注意的是，Li₃[AlP₂O₇F（OH）]（H₂O）_0.5 和 K[Al₂（PO₄）₂F（H₂O）] 都表现出适度的二次谐波产生效应。 此外，K[Al₂（PO₄）₂F（H₂O）] 的多孔材料与 Cs⁺ 表现出显著的离子交换特性，这意味着其在放射性废物修复方面的潜在效用，并为管理核污染物提供了有前途的解决方案。本研究报告了它们的合成、拓扑结构、元素分析、热稳定性、红外拉曼光谱、紫外-可见漫反射光谱、离子交换特性和非线性光学特性。