BaGaPd, BaGaPt, and SrGaPt: Crystal Structure and Chemical Bonding in Relation to BaGaAu and the Zintl Phase SrSi ₂

Three new representatives of the ZrSO structure type (space group P 2 1 3, Pearson symbol cP 12, also known under the notation LaIrSi)—BaGaPd ( a = 6.8660 Å), BaGaPt ( a = 6.8370 Å), and SrGaPt ( a = 6.6144 Å)—are prepared by direct reaction of elements with the subsequent homogenization heat treatment at 600 °C for 500 h. The crystal structure is studied using X‐ray single crystal (BaGaPd) or powder (BaGaPt and SrGaPt) diffraction data. The crystal structures of ZrSO type are crystallographically ordered superstructures of the binary prototype SrSi 2 . Analysis of chemical bonding using quantum chemical techniques in position space reveals the key role of the 3D (anionic) network of covalently‐bonded Ga and transition‐metal atoms TM in {Ba, Sr}[Ga TM ] or silicon atoms in Sr[Si 2 ] for the organization of the crystal structures of SrSi 2 ‐ and ZrSO‐types.