Single crystals of the compounds Li2AeTt (Ae=Ca, Ba, Tt=Si, Ge, Sn, Pb) were grown in reactive lithium melts in sealed tantalum ampoules from an equimolar ratio of the alkaline earth metal and the respective group 4 element. All compounds, with the exception of Li2CaSn and Li2CaPb, are isotypic and crystallize in an orthorhombic unit cell (space group Pmmn, no. 59). The crystal structure can be characterized as superimposed corrugated networks of Li2Tt connected by calcium or barium atoms within the third dimension. Li2CaSn and Li2CaPb crystallize in the cubic space group Fm3̅m (no. 225) in a Heusler-type (MnCu2Al) structure. According to magnetic susceptibility and electric resistivity measurements, the compounds Li2BaGe, Li2BaSn, and Li2BaPb represent diamagnetic activated semiconductors.

A new simple approach to quantitative measures of coordination polyhedra distortions from ideal symmetry is provided with PolyDis. Within the mathematical basis, it minimizes the normalized displacements of given polyhedra to the ideal shape. Applications are discussed, where PolyDis was used to analyze the temperature dependent distortion of LaAlO3, rare earth metal radius dependent distortion of RMnO3 and the increasing structural distortion of (A3N)As with varying alkaline earth metal, all being perovskites. Additionally, the more complex structures of SrCuRSe3 and CsCu3R2Se5 comprising trigonal prisms, octahedra and tetrahedra are treated with PolyDis.

Black single crystals with metallic luster of (Sr3N2/3–x)E (E = Sn, Pb) and (Sr3N)Sb were grown in lithium flux from strontium nitride, Sr2N, and tin, lead, or antimony, respectively. Nitrogen deficiency in the tin and the lead compound is a result of the higher ionic charge of the tetrelide ions E4– as compared to the antimonide ion Sb3–. In contrast to microcrystalline samples from solid state sinter reactions obtained earlier, the flux synthesis induces nitrogen order in the nitrogen deficient tetrelides. The antimony compound crystallizes as inverse cubic perovskite [a = 517.22(5) pm, Z = 1, space group Pm3m, no. 221] with fully occupied nitrogen site, whereas the nitrogen deficient tin and lead compounds exhibit partially ordered arrangements and a certain phase width in respect to nitrogen contents. For the tetrelides, the nitrogen order leads to a cubic 2 × 2 × 2 superstructure [E = Sn: a = 1045.64(8) pm for x = 0, a = 1047.08(7) pm for x = 0.08; and E = Pb: a = 1050.7(1) pm for x = 0, space group Fm3m, no. 225] as derived from single‐crystal X‐ray diffraction data. The metallic tetrelides show diamagnetic behavior, which is consistent with electronic structure calculations.

Powder samples of the compounds (A 3 N)As (A = Mg, Ca, Sr, Ba) were prepared by reacting the respective alkaline earth metal nitrides and arsenic in nickel ampoules. (Mg 3 N)As crystallizes in a cubic unit cell (space group Pm3m, no. 221) with inverse perovskite structure. The analogous compounds of calcium, strontium, and barium crystallize in an orthorhombic unit cell (space group Pnma, no. 62) as

Abstract. Large single crystals of Li 2 (Ca 3 N) 2 [Ga 4 ] and Li 2 (Sr 3 N) 2 [Ga 4 ] up to several mm in size were grown from mixtures of the respective elements and binary alkaline-earth metal nitrides in reactive lithium melts employing a modified high-temperature centrifugation-aided filtration (HTCAF) technique. The main structural features of these iso-