Dimorphism in the REPdZn series

The intermetallic compounds REPdZn (RE = Y, La, Pr, Nd, Sm, Gd–Tm, Lu) were synthesized from the elements in sealed tantalum ampoules in a high-frequency furnace. They were characterized by powder and single crystal X-ray diffraction. The REPdZn phases crystallize with an orthorhombic TiNiSi type high- and a hexagonal ZrNiAl type low-temperature modification. The crystal chemical details are discussed for α- and β-YPdZn. High-pressure high-temperature studies (up to 11.5 GPa, 1570 K) on the structurally closely related intermetallic compounds GdAuZn and TbAuZn gave no hint for pressure-induced phase transitions.