Chemical Bonding Analysis as a Guide for the Preparation of New Compounds: The Case of VIrGe and HfPtGe

The chemical bonding of transition metal compounds with a MgAgAs‐type of crystal structure is analyzed with quantum chemical position‐space techniques. The observed trends in QTAIM Madelung energy and nearest neighbor electron sharing explain the occurrence of recently synthesized MgAgAs‐type compounds, TiPtGe and TaIrGe, at the boundary to the TiNiSi‐type crystal structure. These bonding indicators are used to identify favorable element combinations for new MgAgAs‐type compounds. The new phases—the high‐temperature VIrGe and the low‐temperature HfPtGe—showing this type of crystal structure are prepared and characterized by powder X‐ray diffraction and differential thermal analysis. Chemical bonding models are powerful tools for the systematic preparation of new compounds. In this contribution, quantum‐chemical calculations in position space reveal important trends of chemical bonding that have led to the discovery of two MgAgAs‐type (half‐Heusler) compounds: high‐temperature VIrGe and low‐temperature HfPtGe.