Neue PdxAly-Phasen und die Verbindung Pd5AII2

New Pd_xAl_y Phases and the Compound Pd₅AII₂ The new phases Pd_2.4-2.9Al, Pd_2.99-3.3Al, and Pd_3.8-4.15Al were prepared by synthesis from molten mixtures and subsequent annealing at 600°C, or by reaction in the presence of iodine at 600°C, and were identified by X-ray powder diagrams. In the iodine-containing systems, the same phases resulted from the relation between composition of the gas phase and the structure of the solid reaction component. The existence of Pd₅Al₃ was confirmed. The new compound Pd₅AlI₂, the crystal structure of which was determined from a single crystal X-ray analysis, has a tetragonal layer structure with a = 405.2 and c = 1955.9 pm, space group I4/mmm. Iodine layers alternate with ordered Pd/Al slabs. The compound is a metallic conductor with highly preferred conductivity parallel to the layers.