Single phase powders of (Sr3N)Sb, (Sr3N)Bi ($Pm{\bar 3}m$, No. 221, Z = 1, Sb: a = 517.25(2) pm, V = 138.390(8) · 106 pm3, Bi: a = 520.691(8) pm, V = 141.170(4) · 106 pm3), (Ba3N)Sb, and (Ba3N)Bi (P63/mmc, No. 194, Z = 2, Sb: a = 753.33(3) pm, c = 664.45(3) pm, V = 326.56(2) · 106 pm3, Bi: a = 761.28(4) pm, c = 668.05(3) pm, V = 335.30(2) · 106 pm3) were obtained from reactions of melt beads of the respective elements with bulk compositions of A3E (A = Sr, Ba; E = Sb, Bi) in nitrogen atmosphere of ambient pressure at T = 1070 K (Sr) and T = 1120 K (Ba). The compositions were derived from chemical analyses and supported by Rietveld refinements based on powder X‐ray diffraction patterns. The Sr containing compounds crystallize in the cubic anti‐perovskite type arrangement, the Ba containing compounds in the hexagonal anti‐BaNiO3 structure type. Magnetic susceptibility and electrical resistivity data indicate that the compounds are diamagnetic semiconductors. The optical band gaps of (Sr3N)Sb and (Sr3N)Bi were determined by diffuse reflectivity to 1.15 eV and 0.89 eV, respectively. The experimental results are in agreement with electronic structure calculations. Chemical bonding is characterized in a simplified picture as ionic with significant orbital mixing.

Black powders of (Sr3Nx)Sn (x = 0.74(2), a = 523.51(5) pm), (Ba3Nx)Sn (x = 0.62(2), a = 552.93(1) pm), (Sr3Nx)Pb (x = 0.81(3), a = 524.22(1) pm) and (Ba3Nx)Pb (x = 0.826(4), a = 554.40(3) pm, Pm3¯m, No. 221, Z = 1) were obtained from reactions of melt beads of the respective metals with bulk compositions of A3E (A = Sr, Ba; E = Sn, Pb) in nitrogen atmosphere at temperatures in the range of 970 K ‐ 1220 K. The compositions were derived from chemical analyses, supported by Rietveld refinements based on powder X‐ray and neutron diffraction patterns taken on (Ba3Nx)Sn (x = 0.64(1); neutron diffraction: RBragg = 8.70 %, RF = 6.10 %; X‐ray diffraction: RBragg = 11.60 %, RF = 12.00 %). The phases crystallize in cubic anti‐perovskite type arrangements. Measurements of the magnetic susceptibility indicate a nearly temperature independent paramagnetism. The electrical resistivities are weakly temperature dependent with resistivities at 300 K in the order of 1 mΩ·cm. Electronic structure calculations on ordered superstructures of the composition (A3N2/3)E reveal the phases as intrinsic metals and suggest the tendency towards higher nitrogen site occupation (x > ⅔).

Abstract. The inverse cubic Perovskites (La 3 O)Al, (La 3 N)Al, (Ce 3 O)Al, and (Ce 3 N)Al are reported together with the solid solution series (Ce 3 C 1-x N x )Al. The crystal structure of (La 3 N)Al is analyzed in detail based on single crystal X-ray diffraction data (Space group Pm 3 m, a = 509.04(1) pm, Z = 1, R gt (F) = 0.008, wR(F 2 ) = 0.018). Combined X-ray powder diffraction and thermal analysis studies on samples with various N and O contents indicate only small tolerance of the ternary compounds towards Z = N, O deficiency and small solubility of Z in hexagonal α-Ce 3 Al. Indications for the existence of a cubic β-Ce 3 Al with Cu 3 Au structure type could not be derived from any experiment. All studied phases are metals, the Ce compounds contain the rare-earth metal in Ce(4f 1 ) states according to X-ray absorption spectroscopy and measurements of the magnetic susceptibilities. The Ce moments order antiferromagnetically with T N decreasing and scaling with increasing unit cell dimension of the compounds. Electronic band structure calculations reveal a trend to increased mixing of Z and La states on going from Z = O via N to C. Formation of a band gap even in the formally electronically balanced (La 3 C)Al is mainly prohibited by insufficient charge transfer between the metal species.

The first representatives of 4H (BaMnO3-type structure, P63/mmc, Z = 4) and 9R (BaMnO3-type structure, Rm, Z = 9) inverse Perovskite phases are presented. The phases are obtained within the solid solutions (Sr3-xBaxN)E with E = Bi, Sb. The crystal structures and homogeneity ranges were studied by combined X-ray and neutron diffraction as well as chemical analyses. The cubic Perovskite phase with Bi (Sb) is stable in the range of 0.00 < or = x < or = 0.90(5) (0.00 < or = x < or = 1.30(5)), the 4H variant is stable for 1.55(5) < or = x < or = 2.10(5) (1.85(5) < or = x < or = 2.45(5)), the 9R structure is stable for 2.50(2) < or = x < or = 2.55(2) (2.56(2) < or = x < or = 2.60(2)), and the 2H phase is stable for 2.75(5) < or = x < or = 3.00 (2.80(5) < or = x < or = 3.00). Ba occupies preferable sites in the hexagonal stacking of close packed layers of alkaline earth metal ions and E3-; Sr is mainly located in cubic stacked layers. The phase order upon going from cubic (Sr3N)E to 2H-type (Ba3N)E concomitant to the pronounced Sr/Ba partial order can, in general, be rationalized considering the Coulomb repulsion of nitride ions, as well as the size and charge density of the alkaline earth metal ions.