The structure of an Al₃Mn-type Al₃(Mn, Pd) crystal studied by single-crystal X-ray diffraction analysis

The structure of a single-crystal with a composition of approximately Al₇₅Mn₂₀Pd₅which is isostructural to the ApMn phase, has been investigated by X-ray diffraction analysis. The refinement of the structure was carried out with data from 2197 observed reflections (intensity I > 2.0σ(I)) by the least-squares method to a final R value of 0.062. Pd atoms partially replace Al atoms at definite positions in the Al₃Mn structure and show a mixed occupancy with Al atoms, with their positions significantly shifted along the 6-axis. On the basis of the structure of the Al₃(Mn, Pd) phase, we discuss the positions of Pd atoms in the Al-Pd-Mn decagonal quasicrystal.