High pressure behaviour of PuBi studied by X-ray diffraction

Abstract High-pressure (up to 50 GPa) X-ray diffraction studies were performed on PuBi using energy dispersive techniques with nominal collection angles of 5° and 7°. This compound, which exhibits a NaCl (B1) type structure at ambient pressure, undergoes a crystallographic transition to a tetragonal P 4/ m m m phase at 10 GPa, which remained up to 42 GPa. A second phase transformation to a CsCl-type-structure (B2) occurred above 42 GPa. The first phase transformation is accompanied by a 12% volume collapse; a volume irregularity was not observed for the second transition. The bulk modulus ( B 0 =61 GPa) and its pressure derivative ( B 0 ′=6.1) were calculated for PuBi from its pressure-volume relationship up to the first transition at 10 GPa.