KSbB2O6 and BaSb2B4O12: Novel Boroantimonates with 3D Anionic Architectures Composed of 1D Chains of SbO6 Octahedra and B2O5 Groups

Two new boroantimonates, namely, KSbB2O6 and BaSb2B4O12, have been successfully synthesized through high-temperature solid state reactions. Their structures feature two types of novel anionic 3D frameworks composed of 1D chains of corner-sharing SbO6 octahedra that are interconnected by B2O5 groups. The 1D chains of corner-sharing SbO6 octahedra in polar KSbB2O6 (space group Cc) are extended along the c-axis, whereas those in the centrosymmetric BaSb2B4O12 (space group C2/c) are propagated along the [101] direction. The K+ ions are located at the 1D tunnels of the anionic frameworks along both b- and c-axis, whereas Ba2+ ions are located at the 1D tunnels of the anionic frameworks along both the a- and c-axis. KSbB2O6 is a polar material that displays weak SHG response, whereas BaSb2B4O12 is centrosymmetric and not SHG active. Studies on their optical properties, thermal stability, and band structure calculations based on DFT methods have been also performed.本研究通过高温固相反应法成功合成了两种新型硼锑酸盐（boroantimonates），分别为KSbB2O6与BaSb2B4O12。两种化合物的晶体结构均包含两类新颖的阴离子三维骨架：骨架由共顶点SbO6八面体构筑的一维链经B2O5基团桥联连接而成。其中，极性相KSbB2O6（空间群Cc）中共顶点SbO6八面体形成的一维链沿c轴方向延伸；而中心对称的BaSb2B4O12（空间群C2/c）中对应的一维链则沿[101]方向延展。K+离子位于阴离子骨架沿b轴与c轴方向的一维通道内，Ba2+离子则坐落于阴离子骨架沿a轴与c轴方向的一维通道中。KSbB2O6为极性材料，表现出弱二次谐波产生（Second Harmonic Generation, SHG）响应；而BaSb2B4O12属于中心对称结构，无SHG活性。本研究同时对两种化合物的光学性能、热稳定性进行了表征，并基于密度泛函理论（Density Functional Theory, DFT）开展了能带结构计算。