Figure 3
(a) The equilateral hexagonal prototile that generates the orthorhombic NiZr structure opens up a wide variety of possible tilings including the high-symmetry pentagonal snowflake (b). Whatever the tiling, all atoms apart from the unique central one in (b) share the same kind of environment to first neighbours as in the CrB reference structure. The set (b) describes the whole possible twins in the decomposition from to : each variant can have two adjacent variants, obtained by a rotation [or equivalently by a c mirror in the planes ]. |