Fig. 2.

Atomic structure models of Ce-Al alloy. (A) Rietveld refinement of the new fcc phase at 3.2 GPa synthesized from polycrystalline α-Ce₃Al (wRp = 0.86%, Rp = 0.59%, a = 4.6494 ± 0.0002 Å). The refinement indicates the atoms at the 4 equivalent Fm3m lattice points are indistinguishable, i.e., the fcc phase is a substitutional, solid-solution alloy of Ce₃Al with the Ce occupancy of 0.75 and Al occupancy of 0.25 at lattice points (0, 0, 0), (0,0.5,0.5), (0.5,0.5,0), (0.5,0,0.5). (B) Crystal structures of the 2 ordered compounds α-Ce₃Al and β-Ce₃Al and the disordered fcc-Ce₃Al alloy.