Neudert Lukas, Durach Dajana, Fahrnbauer Felix, Vaughan Gavin B M, Schnick Wolfgang, Oeckler Oliver
Department of Chemistry, University of Munich (LMU) , Butenandtstraße 5-13, 81377 Munich, Germany.
Faculty of Chemistry and Mineralogy, Institute for Mineralogy, Crystallography and Materials Science, Leipzig University , Scharnhorststraße 20, 04275 Leipzig, Germany.
Inorg Chem. 2017 Nov 6;56(21):13070-13077. doi: 10.1021/acs.inorgchem.7b01862.
LaSrSiN with x = 0.489 was obtained as a microcrystalline product by metathesis at 1500 °C in a radio-frequency furnace starting from Si(NH), La(NH), SrH, LaF, and CeF. The structure of the new nitridosilicate oxide fluoride was determined by combining transmission electron microscopy (TEM) and single-crystal X-ray diffraction using a microfocused synchrotron beam. The structure model with pronounced disorder [P6/mmc, Z = 1, a = 16.2065(3), c = 9.4165(1) Å, R(obs) = 0.0436] was confirmed by electron diffraction and aberration-corrected Z-contrast scanning TEM. The highly symmetric AB framework, which was theoretically predicted but not yet realized, consists of all-side vertex-sharing SiN tetrahedra that form channels along [001] filled with La, Sr, O, and F atoms. The connectivity pattern is related to that of tridymite. X-ray spectroscopy and bond-valence-sum calculations were further taken into account for assignment of the N, O, and F atoms.
通过在1500℃的射频炉中，以Si(NH)、La(NH)、SrH、LaF和CeF为原料进行复分解反应，得到了x = 0.489的LaSrSiN微晶产物。利用微聚焦同步辐射束，结合透射电子显微镜（TEM）和单晶X射线衍射确定了新型氮氧化硅氟化物的结构。具有明显无序性的结构模型[P6/mmc，Z = 1，a = 16.2065(3)，c = 9.4165(1) Å，R(obs) = 0.0436]通过电子衍射和像差校正的Z衬度扫描TEM得到了证实。理论上预测但尚未实现的高度对称的AB骨架，由沿[001]方向形成通道的全侧面顶点共享SiN四面体组成，通道中填充有La、Sr、O和F原子。其连接模式与鳞石英的相关。进一步通过X射线光谱和键价和计算来确定N、O和F原子。
