Hübner Julia-Maria, Carrillo-Cabrera Wilder, Prots Yurii, Bobnar Matej, Schwarz Ulrich, Grin Yuri
Chemische Metallkunde, Max-Planck-Institut für Chemische Physik fester Stoffe, Nöthnitzer Straße 40, 01187, Dresden, Germany.
Angew Chem Int Ed Engl. 2019 Sep 9;58(37):12914-12918. doi: 10.1002/anie.201907432. Epub 2019 Aug 19.
The silicon-rich cage compound MgSi was obtained by high-pressure high-temperature synthesis. Initial crystal structure determination by electron diffraction tomography provided the basis for phase analyses in the process of synthesis optimization, finally facilitating the growth of single crystals suitable for X-ray diffraction experiments. The crystal structure of MgSi (space group Cmme, Pearson notation oS24, a=4.4868(2) Å, b=10.1066(5) Å, and c=9.0753(4) Å) constitutes a new type of framework of four-bonded silicon atoms forming Si cages enclosing the Mg atoms. Two types of smaller Si cages remain empty. The atomic interactions are characterized by two-center two-electron bonds within the silicon framework. In addition, there is evidence for multi-center Mg-Si bonding in the large cavities of the framework and for lone-pair-like interactions in the smaller empty voids.
通过高温高压合成获得了富含硅的笼状化合物MgSi。通过电子衍射断层扫描进行的初始晶体结构测定为合成优化过程中的相分析提供了基础，最终促进了适合X射线衍射实验的单晶生长。MgSi的晶体结构（空间群Cmme，皮尔逊符号oS24，a = 4.4868(2) Å，b = 10.1066(5) Å，c = 9.0753(4) Å）构成了一种新型的由四键合硅原子形成包围Mg原子的Si笼的框架。两种较小的Si笼是空的。原子间相互作用的特征是硅框架内的双中心双电子键。此外，有证据表明在框架的大空洞中存在多中心Mg-Si键，在较小的空穴中存在类似孤对的相互作用。
