Rubidium and Cesium Nitrides at Megabar Pressures

In our recent investigations, we discovered a plethora of new rubidium–nitrogen and cesium–nitrogen compounds—i.e. a staggering 11 new solids—at pressures up to 50 GPa. However, no investigation on alkali metals–N systems beyond 60 GPa has been reported in the literature, and there is no doubt that many more new alkali metals polynitrides remain to be discovered at these higher pressures. Through the investigation of the Rb–N and Cs–N systems up to 180 GPa, this proposal aims at forming compounds comprised of new exotic nitrogen species and assessing their recovery to ambient conditions. The solids’ crystal structure will be determined by single-crystal X-ray diffraction, also employed to determine the novel materials’ stability domain and recoverability to ambient conditions.