High-pressure synthesis of one-dimensional alkaline-earth palladates

Three novel one-dimensional alkaline-earth palladates were synthesized at high pressure. Ca4PdO6, Sr4PdO6, and Sr3(Sr0.75Pd0.25)PdO6 are all found to be of the K4CdCl6 (Sr4PtO6) structure in a trigonal cell of space group R-3c (No. 167). This structure consists of infinite chains of face-shared alternating PdO6 octahedra and distorted trigonal prisms along the c-axis. The chains are separated by alkaline-earth cations. All three palladates showed weak diamagnetism in preliminary measurement.