The recently published two-step ammonolysis was adapted to the first synthesis of GaFe 3 N as a pure phase and AlFe 3 N with a very high phase purity. Similar to archetypal γ 0 -Fe 4 N (a = 3.7900(6) A ˚), the ternary nitride GaFe 3 N adopts a perovskite-like structure in space group Pm3m with a slightly enlarged lattice parameter of a = 3.7974(1) A ˚. The magnetic characterization clearly evidences that GaFe 3 N is an antiferromagnet. The systematic exchange of Ga by Fe in going from GaFe 3 N to γ 0 -Fe 4 N results in a change from antiferromagnetic to ferromagnetic behavior. In contrast, the homologous ternary nitride AlFe 3 N shows a statistical Al/Fe substitution which results in space group Fm3m. AlFe 3 N can be classified as a soft ferromagnetic nitride.

Predictions confirmed: The phase RhFe3N (see unit cell), which was recently predicted by total‐energy density functional calculations and proposed to have exciting magnetic properties, was synthesized for the first time. The experimental lattice parameter is in good agreement with the theoretical prediction, and the phase appears to be a semihard itinerant ferromagnet. The atomic magnetic saturation moment, ${{\mu {{{\rm {\rm s}}\hfill \atop {\rm {\rm a}}\hfill}}}}$, is 8.3 μB per formula unit, and the Curie temperature, TC, is 505(25) K.

The recently published two-step ammonolysis reaction giving access to phase-pure GaFe(3)N has been reinvestigated. Thermochemical calculations show that a high-temperature route is necessary to avoid the formation of the competing GaN phase. Compared to the prior study showing a Vegard-like behavior (that is, a linear correlation between lattice parameter and elemental composition), improved X-ray analysis using Mo Kα(1) radiation in combination with density-functional theory calculations reveal a more complicated behavior of the lattice parameter within the entire Ga(x)Fe(4-x)N series. The new finding originates from the magnetic properties, and the change in the magnetic ordering with increasing Ga content from ferromagnetic γ'-Fe(4)N to antiferromagnetically ordered GaFe(3)N, as observed from susceptibility measurements, is reproduced by different theoretical spin-alignment models, that is, a systematic evaluation of several antiferromagnetic spin orientations. Nonetheless, all structural models are based on the favored atomic ordering for GaFe(3)N, explainable by the strong affinity between iron and nitrogen.

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