A new cluster-based cubic phase in the Al–Cu–Ir system

The structure of the intermetallic phase cF244-Al63.3Cu12.3Ir24.4, a superstructure of a 1/0-approximant to an icosahedral quasicrystal, was determined by single-crystal X-ray diffraction. It can be described as a packing of endohedral clusters with a significant amount of disorder in the innermost shells. Similarities to the structures of related intermetallic compounds and quasicrystal approximants are discussed.