Structural Prediction Based on CALYPSO and First‐Principles Calculations of Elastic and Electronic Properties of MgSc ₂ S ₄

A systematic crystal structure search for MgSc 2 S 4 was performed using the CALYPSO method combined with first‐principles calculations. Six new energetically competitive structures were predicted, with space groups , C 2/ m , Imma , I 4 1 / amd , , and P 6 3 mc . All six phases are dynamically stable, as confirmed by phonon calculations, and satisfy the Born criteria for mechanical stability. Negative formation enthalpies indicate thermodynamic stability and potential synthesizability. The predicted elastic properties reveal distinct mechanical behaviors among the six phases: the Imma and I 4 1 / amd structures exhibit higher elastic moduli and moderate anisotropy, whereas the and P 6 3 mc structures display pronounced anisotropy with lower resistance to deformation along the c ‐axis. Electronic structure calculations reveal that all these phases are semiconductors with bandgaps ranging from 1.63 ( Imma ) to 3.27 eV ( P 6 3 mc ). The Imma and I 4 1 / amd phases exhibit direct bandgaps, while the other four structures possess indirect character. These findings expand the known phase space of MgSc 2 S 4 and provide guidance for phase‐selective synthesis and property‐oriented design of this material system.