Re-Refinement of [alpha]-(AlMnSi)

Crystals of the [alpha]-(AlMnSi) (aluminium manganese silicon alloy, Al₄Mn_1.01Si_0.74) cubic 1/1 approximant phase for the icosahedral quasi-crystal were prepared from an Al₇₂Mn₁₆Si₁₂ alloy under an argon atmosphere. The structure is reproduced by the connection of two large atom clusters with icosahedral symmetry (a Mackay icosahedron and double-Mackay icosahedron) [Yang (1988). Phil. Mag. B58, 47-57]. Si and Mn atoms are suggested to constitute icosahedral arrangements in the atom clusters. The crystal structure of [alpha]-(AlMnSi) was determined previously by Cooper & Robinson [Acta Cryst. (1966), 20, 614-617].

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