Synthesis and crystal structure of MgB12Si2—The first ternary compound in the system B/Mg/Si

We report on the synthesis of MgB12Si2 the first ternary compound in the system B/Mg/Si. Yellow transparent single crystals were yielded from the elements at 1600 °C in h-BN crucibles welded in Ta ampoules. MgB12Si2 crystallizes orthorhombic in the space group Pnma   with a=10.9797(11)Å, b=6.1098(7)Å, c=8.3646(12)Å and Z=4Z=4. The crystal structure is characterized by layers of B12 icosahedra, connected by isolated Si atoms to a three-dimensional framework. Mg atoms are placed in voids of the framework. Each icosahedron forms 8 B–Si bonds and 4 exohedral B–B bonds. The Si atoms are tetrahedrally coordinated by B atoms of the B12 icosahedra.

Graphical abstractThe crystal structure of MgB12Si2, the first ternary compound of the system Mg/B/Si, is characterized by layers of B12 icosahedra, connected by isolated Si atoms to a three dimensional framework. Mg atoms are placed in voids of the framework.Figure optionsDownload full-size imageDownload as PowerPoint slide