Boric acid flux synthesis, structure and magnetic property of MB12O14(OH)10 (M=Mn, Fe, Zn)
Boric acid flux synthesis, structure and magnetic property of MB12O14(OH)10 (M=Mn, Fe, Zn)
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DOI：
10.1016/j.jssc.2013.02.017
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发表时间：
2013-05
影响因子：
3.3
通讯作者：
Dingfeng Yang;Rihong Cong;Wenliang Gao;Tao Yang
中科院分区：
文献类型：
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作者：
Dingfeng Yang;Rihong Cong;Wenliang Gao;Tao Yang
采用硼酸通量法合成了三种新型硼酸盐MB12O14(OH)10(M=Mn, Fe, Zn)，它们与NiB12O14(OH)10具有同型性。采用单晶XRD对晶体结构进行了详细分析。它们均在单斜空间群P21/c中结晶。MO6（M=Mg, Mn, Fe, Co, Ni, Zn）八面体的尺寸与M2+的Shannon有效离子半径符合较好。磁性测量表明MnB12O14(OH)10是反铁磁性的，没有低至2K的长程序。用离散傅立叶变换计算了其磁超交换常数的值，解释了观察到的磁行为。ZnB12O14(OH)10的紫外-可见漫反射光谱显示带隙为4.6eV。DFT计算表明其直接带隙为4.9eV。光学带隙是由电荷从已占据的o2p态转移到未占据的zn4s态造成的。
Three new borates MB12O14(OH)10(M=Mn, Fe, Zn) have been synthesized by boric acid flux methods, which are isotypic to NiB12O14(OH)10. Single-crystal XRD was performed to determine the crystal structures in detail. They all crystallize in the monoclinic space group P21/c. The size of MO6(M=Mg, Mn, Fe, Co, Ni, Zn) octahedron shows a good agreement with the Shannon effective ionic radii of M2+. Magnetic measurements indicate MnB12O14(OH)10is antiferromagnetic without a long-range ordering down to 2K. The values of its magnetic superexchange constants were evaluated by DFT calculations, which explain the observed magnetic behavior. The UV–vis diffuse reflectance spectrum of ZnB12O14(OH)10suggests a band gap ∼4.6eV. DFT calculations indicate it has a direct band gap 4.9eV. The optical band gap is contributed by charge transfers from the occupied O 2p to the unoccupied Zn 4s states.