Inter-element miscibility driven stabilization of ordered pseudo-binary alloy.

An infinite number of crystal structures in a multicomponent alloy with a specific atomic ratio can be devised, although only thermodynamically-stable phases can be formed. Here, we experimentally show the first example of a layer-structured pseudo-binary alloy, theoretically called Z3-FePd. This Z3 structure is achieved by adding a small amount of In, which is immiscible with Fe but miscible with Pd and consists of an alternate L1 (CuAu-type)-PdFePd trilayer and Pd-In ordered alloy monolayer along the c axis.

Determinants of crystal structure transformation of ionic nanocrystals in cation exchange reactions.

Changes in the crystal system of an ionic nanocrystal during a cation exchange reaction are unusual yet remain to be systematically investigated. In this study, chemical synthesis and computational modeling demonstrated that the height of hexagonal-prism roxbyite (CuS) nanocrystals with a distorted hexagonal close-packed sulfide anion (S) sublattice determines the final crystal phase of the cation-exchanged products with Co [wurtzite cobalt sulfide (CoS) with hexagonal close-packed S and/or cobalt pentlandite (CoS) with cubic close-packed S]. Thermodynamic instability of exposed planes drives reconstruction of anion frameworks under mild reaction conditions.