Reshak Ali Hussain, Chen Xuean, Song Fangping, Kityk I V, Auluck S
Institute of Physical Biology, South Bohemia University, Nove Hrady 37333, Czech Republic. Institute of System Biology and Ecology, Academy of Sciences, Nove Hrady 37333, Czech Republic.
J Phys Condens Matter. 2009 May 20;21(20):205402. doi: 10.1088/0953-8984/21/20/205402. Epub 2009 Apr 24.
A non-centrosymmetric borate, CaBiGaB(2)O(7), has been grown by a solid-state reaction method at a temperature below 700 °C. The single-crystal x-ray structural analysis has shown that it crystallizes in the tetragonal space group [Formula: see text] with a = 0.7457(1) nm, c = 0.4834(1) nm, Z = 2. It has a three-dimensional (3D) structure in which B(2)O(7) groups are bridged by GaO(4) tetrahedra through shared O atoms to form 2D [Formula: see text] layers that are further linked by Bi(3+)/Ca(2+) cations giving rise to the final 3D framework. The IR spectrum confirms the presence of BO(4) groups and the UV-vis diffuse reflectance spectrum shows that the optical band gap is about 2.9 eV. This value is compared with our band structure calculations using the full potential linearized augmented plane wave approach within the framework of the Engel-Vosko GGA formalism.
一种非中心对称硼酸盐CaBiGaB₂O₇已通过固态反应法在700°C以下的温度下生长出来。单晶X射线结构分析表明，它结晶于四方空间群[化学式：见正文]，a = 0.7457(1) nm，c = 0.4834(1) nm，Z = 2。它具有三维（3D）结构，其中[B₂O₇]⁸⁻基团通过共用O原子被[GaO₄]⁵⁻四面体桥接，形成二维[化学式：见正文]层，这些层通过Bi³⁺/Ca²⁺阳离子进一步连接，形成最终的3D框架。红外光谱证实了[BO₄]⁵⁻基团的存在，紫外-可见漫反射光谱表明光学带隙约为2.9 eV。该值与我们在Engel-Vosko广义梯度近似（GGA）形式框架内使用全势线性缀加平面波方法进行的能带结构计算结果进行了比较。
