Understanding Formation of the InPd3 Polymorphs: A DFT Study

The intriguing experimental results regarding the synthesis and structure types adopted by binary InPd3 have been fundamentally addressed using first-principles density functional theory calculations. Longer annealing time at higher temperature leads to stronger and more optimized heteroatomic In-Pd contacts that result in the extended ordering between them and leading to the ZrAl3-structure type; followed by another ordered derivative TiAl3-type and the metastable disordered AuCu-type when the annealing time and temperature were reduced. The thermodynamic stability order of these three polymorphs of InPd3; i.e. ZrAl3-type > TiAl3-type > AuCu-type is understood from the correlation between formation enthalpies, Madelung energies, and electronic structure, chemical bonding analysis.