High pressure study and bonding analysis of Mg2Co3Sn10+xMg2Co3Sn10+x

Intermetallic materials with large unit cells are scientifically interesting and challenging due to their structural and chemical complexity. The investigated hexagonal Mg2Co3Sn10+xMg2Co3Sn10+x crystallizes with 120 atoms per unit cell and a unit cell volume of 2655 Å3. An in-house single-crystal high pressure study was done using a recently developed low background diamond-anvil cell. The investigated compound is structurally stable up to the highest reached pressure of 9.69 GPa. Compressibility measurements revealed the c⇒-axis to be slightly less compressible than the a⇒-axis. A chemical bonding analysis based on the analysis of the topology of the electron localization function identified Mg2Co3Sn10+xMg2Co3Sn10+x as a compound combining localized and delocalized chemical bonding in its structure. The macroscopic properties of the compound are dominated by the metallic 3D framework, which is also responsible for the anisotropic compressibility.

Mg2Co3Sn10+xMg2Co3Sn10+x belongs to the fascinating group of compounds combining localized and delocalized chemical bonding of the same element type in their structure. The structural stability up to 9.69 GPa and chemical bonding of this complex metallic alloy (120 atoms per unit cell) is reported.Figure optionsDownload full-size imageDownload as PowerPoint slide