Unveiling the behaviour of borax and probertite at non-ambient conditions

This proposal is devoted to study the structural evolution and the P-T stability of borax and probertite, two natural hydrated borates mineral. Critically, borax is one of the main ore minerals of boron, a critical element for the European Union since 2014. In the last years, our team have studied several hydrated borates, each one displaying one (or more) phase transition at high-pressure in the P-range 1.6-17 GPa. These studies suggest a correlation between the H2O content and the pressure at which a hydrated borate undergoes a phase transition, but more studies are needed to confirm a real trend. The main goals of this project are: i) to assess the high-pressure and the combined high-temperature/high-pressure stability range of these minerals, ii) to unravel the P-deformation mechanisms of borax and probertite, at the atomic scale iii) to collect high-quality single-crystal data in order to solve the structure of their high-pressure polymorphs.