Pressure-induced amorphization in mayenite (12CaO·7Al2O3).

We report a joint experimental and theoretical study on high pressure structures of nanoporous mayenite (12CaO·7Al(2)O(3)). A pressure-induced amorphization was identified at ∼13 GPa by in situ high pressure x-ray experiments. The amorphous product can be decompressed to ambient conditions. Ab initio calculations reveal that the anisotropic deformations of empty cages break the crystallographic long-range orders, leading to the formation of high-pressure amorphous state. Furthermore, the deformation routes of empty cages are found fully dependent on their individual locally structural geometry relevant to the distribution of extra-framework oxygen ions.