All the disorder mechanisms in the 13:58 phases come together. Out of the modulated confusion rises the remarkable phase Ce12.60Cd58.68(2).

The compound Ce12.60Cd58.68(2) is a metrically commensurate representative of the incommensurately modulated phase Ce13Cd57+delta. It is most likely a lock-in phase. The structure, which was solved using seeding of the modulation from those positions most affected as well as direct solution by charge flipping, represents a rare case of ordering in a family of structures where disorder is the rule. The disorder mechanisms, known from other RE13Zn/Cd58 phases, order in this phase to give rise to a remarkable interplay between interstitials and vacancies. The compound crystallizes in the super space group Ccmm(alpha00)00s (standard setting Amma(00gamma)s00) with cell parameters a=27.2789(14) A, b=15.7592(1) A, and c=15.5816(4) A and a q vector close to 2/3.