Zr₃Mn₃Sn₄Ga: a new hexagonal Ti₆Sn₅-type quaternary intermetallic

The discovery of a new quaternary intermetallic compound of composition Zr₃Mn₃Sn₄Ga during a survey of the Zr–Mn–Sn–Ga phase diagram is reported. Single-crystal X-ray diffraction reveals that the new compound crystallizes in a hexagonal lattice (space group P6₃/mmc, No. 194). The analysis of single-crystal X-ray diffraction data indicates that the atomic arrangement is an ordered variant of the high-temperature hexagonal Ti₆Sn₅ crystal structure. From a simple geometry point of view, the unit cell consists of GaZr₃ octahedra chains and Mn chains growing along the sixfold symmetry axis c. The Mn chains are stacked within the ab basal plane in a kagome geometry, with large interatomic distances. The possible slight levels of Sn/Ga and Zr/Mn mixed occupancy based on additional results of electron probe microanalysis and single-crystal neutron diffraction are discussed. It is noteworthy that this compound is the first quaternary intermetallic discovered in this structure and the first Ti₆Sn₅ derivative bearing a magnetic metal, namely Mn, in the 6g position, which may give rise to interesting physical properties.