Zn3(C6H14N2)3[B6P12O39(OH)12] · (C6H14N2)[HPO4]: A Chiral Borophosphate – Triethylenediammonium Hydrogenphosphate Composite

A novel borophosphate, Zn₃(C₆H₁₄N₂)₃[B₆P₁₂O₃₉(OH)₁₂] · (C₆H₁₄N₂)[HPO₄] has been synthesised under mild hydrothermal conditions at T = 165 °C. The chiral crystal structure was determined by single crystal X‐ray diffraction data (trigonal, R3 (no. 146), Z = 3, a = 2089.55(4) pm, c = 1237.03(4) pm, V = 4677.5(2) · 10⁶ pm³, R₁ = 0.066, wR₂ = 0.164 for 5100 observed reflections). The title compound can be considered as an ordered composite of the two different and neutral structures which fit into each other: An open framework of composition Zn₃(C₆H₁₄N₂)₃[B₆P₁₂O₃₉(OH)₁₂] and columns of composition (C₆H₁₄N₂)[HPO₄]. The framework structure is formed by mixed octahedral‐tetrahedral secondary building units, in a three‐dimensional arrangement reflecting a hierarchical derivative of the NbO structure type. The underlying NbO topology is illustrated with the help of Periodic Nodal Surfaces. The composite nature of the compound is resolved in the spatial segregation of two frameworks with a separating surface.     

Ba2[Ni3N2]: a low-valent nitridonickelate-synthesis, crystal structure, and physical properties

The ternary alkaline-earth nitridonickelate Ba2[Ni3N2] (Ba2[NiI2Ni0N2]) was prepared by the reaction of mixtures of Ba2N and Ni in nitrogen gas of ambient back-pressure at 1173 K. The crystal structure determined by X-ray single-crystal and powder diffraction methods as well as from neutron diffraction data at various temperatures between 2 and 298 K is orthorhombic (Cmca (no. 64), 298 K: a=715.27(18) pm, b=1032.99(21) pm, c=740.12(20) pm) and provides the first example of a nitridonickelate with a two-dimensional complex anion. The Ni2 atom is described with a split position and the corresponding superstructure variants are investigated by theoretical full-potential nonorthogonal local-orbital calculations (FPLO). The average oxidation state of Ni in Ba2[Ni3N2] is +0.67, the lowest average value observed in nitridonickelates so far. Investigations of the physical properties demonstrate that Ba2[Ni3N2] acts as a "poor" metal with a large resistivity of approximately 2.7 mOmega cm at 300 K and exhibits low-dimensional magnetism with antiferromagnetic ordering at T approximately 90 K. XAS spectra correspond with low-valent Ni states.     

Crystal Chemistry of Ternary and Quaternary Transition Metal Nitrides

Nitrides are fascinating materials. Although the air we breathe is 78% nitrogen, essentially 100% of the land we walk upon are made of oxides. It would take an encyclopaedia to review oxide crystal chemistry, on the other hand we can present here a comprehensive review of ternary and quaternary solid state nitrides. In the ternary and quaternary solid state nitrides (IA,IIA)-M-N, unusual low valence M⁺ were found for copper, nickel, cobalt, iron and manganese, and various MN_n transition metal-nitrogen coordination polyhedra with CN=2(linear), 3(trigonal-planar), 4(tetrahedral and square planar), 5(square pyramidal), and 6(octahedral and trigonal prismatic) and different fashions of connection make nitrides an important family of inorganic solid state materials. A suitable classification is made on the basis of the correlation between coordination numbers (CN), the connection fashions and oxidation states of the anionic principal structures.