Dolomite-type MSn(BO3)2 phases for M = Mn, Fe, Co and Ni have been synthesized using solid-state synthesis carried out in sealed quartz tubes. X-ray powder diffractiondata Rietveld refinements confirm the rhombohedral space group R 3 ‾ $R\overline{3}$ for all compositions. The change in unit-cell parameters follows the increasing nature of the radius of the M-cations. Both the MO6 and SnO6 octahedra are found to be quite regular. 119Sn Mössbauer spectroscopy investigations complement the almost undistorted nature of the SnO6 octahedra and the tetra-valent charge of the tin-atoms. Detailed vibrational features are described from the Raman and the FTIR spectral data collected at ambient conditions. The frequency shifts of some selective Raman and IR bands are explained in terms of the change of cationic sizes and the respective M–O bond distances. The UV/Vis diffuse reflectance data are analyzed using the RATD method, leading to direct bandgaps for all the investigated samples. The wide bandgap semiconductors (3 – 4 eV) show increasing transition energies with increasing cation sizes of the high-spin M-cations in the dolomite types.

中文翻译：

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M = Mn、Fe、Co 和 Ni 的白云石型 MSn(BO3)2 的合成、结构和光谱研究

白云石型MSn(BO3个)2个M = Mn、Fe、Co 和 Ni 的相已使用在密封石英管中进行的固态合成合成。X 射线粉末衍射数据 Rietveld 精修确认菱面体空间群 R 3个 ‾ $R\上划线{3}$ 对于所有作品。晶胞参数的变化遵循 M 阳离子半径的增加性质。无论是 MO6个和二氧化锡6个发现八面体非常规则。119Sn Mössbauer 光谱研究补充了 SnO 几乎未失真的性质6个八面体和锡原子的四价电荷。从在环境条件下收集的拉曼和 FTIR 光谱数据描述了详细的振动特征。一些选择性拉曼和红外波段的频移可以根据阳离子大小和相应的 M-O 键距的变化来解释。使用 RATD 方法分析 UV/Vis 漫反射数据，导致所有研究样品的直接带隙。宽带隙半导体 (3 – 4 eV) 显示出随着白云石类型中高自旋 M 阳离子的阳离子尺寸增加而增加的跃迁能量。