High-pressure structural studies of uranium and thorium compounds with the rocksalt structure

High-pressure X-ray diffraction studies have been performed on uranium and thorium rocksalt-structure compounds. Bulk modulus B0 and its pressure derivative B0′ have been determined. Pressure-induced first order phase transformations have been found for UC and UN, second order transitions for US, UP and ThS. No transition is found for ThC and ThN up to 40–45 GPa