In Situ Very-High-Energy Diffraction Studies of Thermal Decomposition of Transition Metal Trifluorides

The thermal decomposition of transition metal trifluorides MF3 (M = Mn, Fe, Co) was studied by collecting sequences of very-high-energy (89 keV) synchrotron radiation diffraction patterns. The real-time evolution of the crystal lattices was followed as a function of temperature and it was observed that the transition from MF3 to MF2 is generally accompanied by the formation of intermediate short-living phases –M2F5. One of them –Co2F5– is a phase which had never been observed before.