Abstract
An inter-metallic phase in the Al-Mn-Ni system crystallizing in space group Cmcm (No. 63) and refined formula Al(61.49)Mn(11.35)Ni(4) (called the R' phase) has been synthesized by high-temperature sinter-ing of a mixture with initial chemical composition Al(60)Mn(7)Ni(3). In comparison with the structure model of the previously reported R phase with composition Al(60)Mn(11)Ni(4) [Robinson (1954 ▸). Acta Cryst. 7, 494-497], there are two mutually exchanged Mn and Ni sites together with one positionally disordered Al site [occupancy ratio 0.811 (8):0.121 (7)] and one partially occupied Mn site [s.o.f. 0.677 (5)] in the current structure model of the R' phase.