Crystal structure of the Chevrel phase SnMo6S8 at high pressure

The high-pressure behavior of the Chevrel phase SnMo6S8 was investigated by angular dispersive synchrotron powder diffraction. The experiments were accompanied by first principles calculations at the density functional theory level. The fit of a Birch-Murnaghan equation-of-state gave the volume at zero pressure V0=277(1) Å3, the bulk modulus at zero pressure B0=84(3) GPa, and the pressure derivative of the bulk modulus B′=3.0(4) for the experimental data and V0=281.6(3) Å3, B0=76(1) GPa, and B′=4.7(1) for the calculated data. The analysis of the bond distances and the bond population reveals the formation of new bonds and changes of the bond characteristics in the structure under pressure. The compression mechanism is analysed by means of the distortion of the Mo6S8 cluster and the rotation of the cluster with respect to the unit cell edges.