Structural stability of URh3 at high pressure

URh3 stabilizes in the cubic AuCu3 type structure at normal temperature and pressure. High-pressure angle-dispersive X-ray diffraction experiments were performed on URh3 up to 25 GPa using a diamond-anvil cell. URh3 remains in its cubic AuCu3 type structure up to the maximum pressure studied. The Birch-Murnaghan equation of state fit to the P-V data yields the bulk modulus to be 133 GPa. The Villars structural stability map gives a clue of a possible high pressure phase transition to a Ni3Sn type structure. The electronic structure calculations were carried out for both the ambient AuCu3 type cubic phase and the expected Ni3Sn type hexagonal high pressure phase. However, the total energy curves of these two structures do not intersect even at pressure as high as 360 GPa, removing the possibility of transition to Ni3Sn type structure.