MgAuGa and MgAu₂Ga: first representatives of the Mg-Au-Ga system

MgAuGa is the first ternary representative of the Mg-Au-Ga system. It adopts the Fe₂P structure type (Pearson symbol hP9) and closely resembles hexa­gonal Mg₂Ga through a direct group-subgroup relationship. MgAu₂Ga also crystallizes hexa­gonally and is isotypic with Na₃As. It adopts the structure of another binary compound, viz. Mg₃Au (hP8), but shows an unexpected distribution of Mg, Au, and Ga among the atomic positions of the asymmetric unit compared to Mg₃Au.