Ca₂[FeN₂l und Sr₂IFeN₂]: Nitridoferrate(II) mit isolierten Anionen [Fe₂N₄]⁸⁻ und [FeN₂]⁴⁻/Ca₂[FeN₂] and Sr₂[FeN₂]: Nitridoferrates(II) with Isolated Anions [Fe₂N₄]⁸⁻ and [FeN₂]⁴⁻

Ca 2 [FeN 2 ] (monocl., C2/m (No. 12); a = 1093.0(2) pm, b = 496.0(1) pm, c = 684.4(1) pm, β = 121.09(1)°; Z = 4) and Sr 2 [FeN 2 ] (tricl., P1̄ (No. 2); a = 653.8(1) pm, b = 869.0(2) pm, c = 893.2(2) pm, α = 90.22(2)°, β = 109.45(1)°, γ = 102.30(1)°; Z = 5) were prepared by reaction of mixtures Ca 3 N 2 /Fe (Sr 2 N/Fe) with nitrogen (1 atm) at 850 C. The crystal structure of Ca 2 [FeN 2 ] contains isolated planar anions [Fe 2 N 4 ] 8- ; in the crystal structure of Sr 2 [FeN 2 ] planar [Fe 2 N 4 ] 8- units are present as well as linear anions [FeN 2 ] 4- .