Y 4 Ni 0.71 Ag 1.29 : Expanding the Boundaries of the Gd 4 RhIn Structure Type

The new ternary compound Y 4 Ni 0.71 Ag 1.29 has been prepared by arc melting the elements under inert atmosphere. Subsequent annealing at 800°C for 2 weeks yielded crystals of sufficient quality for structure determination by single‐crystal X‐ray diffraction. Y 4 Ni 0.71 Ag 1.29 crystallizes with space group F 3 m , cF 112, a = 13.5653(8) Å, V = 2496.3(4) Å 3 , Z = 16. Its crystal structure represents a ternary, disordered variant of the Gd 4 RhIn type, with Ni positions corresponding to the Rh sites and Ag positions to the In sites of the prototype. Y 4 Ni 0.71 Ag 1.29 is the first representative of this type with three transition metals, exhibiting an unique distribution of its components. Electronic structure calculations were performed for an idealized stoichiometric Y 4 NiAg to understand the origins of nonstoichiometry, which reveal that adjusting the composition to Y 4 Ni 0.71 Ag 1.29 leads to an optimization of the electronic structure.