The structure of Al₃Mn: Close relationship to decagonal quasicrystais

The crystal structure of the Al3Mn phase, considered to be closely related to that of decagonal auasicrystais, has been determined by a combination of single-crystal X-ray analysis and high-resolution electron microscopy. The atomic model, obtained from a Patterson synthesis and high-resolution electron microscopy, was refined by the least-sauares methods with the Unics III system to a final R value of 0.066. There are 156 atoms in an orthorhombic unit cell with the lattice parameters a=1.483 nm, b=1.243 nm and c=1.251 nm, and the space group is Pnma (No. 62). Based on the structure of Al3Mn, an atomie arrangement for the Al-Pd-Mn decagonal quasicrystal is discussed.