Speciation of nitrogen - [N(3-)] and [N(2)(2-)] - in binary compounds

The nitrogen content of the binary compounds SrN = Sr(4)[N](2)[N(2)], Sr[N(2)], and Ba[N(2)] (prepared by high-pressure syntheses) was determined analytically by using the carrier gas hot extraction method. For handling of the air- and moisture-sensitive samples, a transfer chamber was constructed to protect the compounds against decomposition before being analyzed. Additionally, it was necessary to develop a method allowing controlled and variable heating of the electrode furnace to get analytical results with high precision and accuracy. By means of a suitable temperature program it was possible not only to verify the existence but also to quantify the two different nitrogen species ([N(3-)] and [N(2)(2-)]), and thus confirm the results of recent neutron diffraction studies.     

Preparation,Crystallographic, Spectroscopic and Magnetic Characterization of Low‐Valency Nitridometalates Li2[(Li1‐xMx)N] with M = Cu,Ni

Thermogravimetric and difference thermal analyses show that the reactions of lithium nitride with the transition metals Cu and Ni under molecular nitrogen to form phases Li₂[(Li_1‐xM^I_x)N] take place above 673 K. The maximum weight gains are reached at 926 K and 968 K for M = Cu and Ni, respectively. At higher temperatures, the ternary phases Li₂[(Li_1‐xM^I_x)N] decompose, limiting the substitutional level x. In the temperature range of 773 K — 873 K, the successful synthesis of Li₂[(Li_1‐xNi^I_x)N] (0 < x ≤ 0.85(1)) single phase products is demonstrated. Maximum substitution obtained for the Cu phases is x_max= 0.43(1). The dependence of the lattice parameters of the hexagonal unit cell on x is almost linear. The magnetic moment of M strongly depends on x. At low x the magnetic moments in phases with M = Ni are presumably enhanced by orbital effects. A decrease of μ_eff with x to μ_eff(x = 1) → 0 is explained by delocalization of the magnetic moments and by the gradual formation of a metal for the hypothetical compound Li₂[NiN] (x = 1). XAS spectroscopy at the transition metal K‐edges shows that Cu and Ni principally correspond to d¹⁰‐ and d⁹‐configurations, respectively.     

Crystal structures of two polymorphs of Ca3[Al2N4

Green transparent single crystals of alpha-Ca3[Al2N4] (monoclinic, P2(1)/c, No. 14, a = 957.2(3) pm, b = 580.2(3) pm, c = 956.3(5) pm, beta = 111.62(3) degrees; Z = 4) were obtained from reactions of mixtures of the representative metals with nitrogen above temperatures of 1000 degrees C. beta-Ca3[Al2N4] (monoclinic, C2/c, No. 15, a = 1060.6(2) pm, b = 826.0(2) pm, c = 551.7(1) pm, beta = 92.1(1) degrees; Z = 4) was formed as a byproduct of a reaction of calcium with alumina under nitrogen at T = 930 degrees C in form of colorless crystals. The crystal structures of the two polymorphs contain edge- and corner-sharing AlN4 tetrahedra, leading to different layered anionic partial structures: infinity 2[AlN2/2N2/3)2(AlNN2/2N1/3)6/3(12-)] in the alpha-phase and infinity 2[Al2N2N4/2(6-)] in the beta-polymorph.     

[C10N2H10][ZnCl(HPO4)]2: A New Templated Zincophosphate Containing Tetrahedral Nets with 63 Topology

The crystal structure of [C₁₀N₂H₁₀][ZnCl(HPO₄)]₂ contains corrugated tetrahedral layers with 6³ topology. Charge balance is achieved by insertion of diprotonated 4,4′‐bipyridine between the layers. Crystal data: monoclinic, P2₁/n (no. 14), a = 4.8832(2) Å, b = 22.673(2) Å, c = 8.1643(4) Å, β = 104.02(1)°; V = 877.0(1) ų; Z = 4; R1 = 0.041 and wR2 = 0.088 for 1836 reflections [I > 2σ(I)]. Tetrahedral layers are also observed in other organo‐ammonium templated compounds. However, their topologies are characterized by 4.8² nets. With the title compound a layered tetrahedral net with 6³‐topology is reported for the first time.     

Kristallstrukturen von Säurehydraten und Oxoniumsalzen. XVI Zur Kenntnis der Verbindung H2TeI6 · 8 H2O

Crystal Structures of Acid Hydrates and Oxonium Salts. XVI. On the Compound H₂TeI₆ · 8 H₂O Crystals of H₂TeI₆ · 8H₂O are obtained as dark-brown needles with a metallic lustre in incident light from solutions of tellurium iodides in concentrated hydroiodic acid on cooling. Under standard conditions the phase is stable only in contact with its saturated solution; decomposition by formation of HI, H₂O, and TeI₄ takes place in vacuo. H₂TeI₆ · 8 H₂O is orthorhombic, space group Pnnm, Z = 2, with a = 12.672(15) Å, b = 10.825(14) Å, c = 8.322(8) Å. Structurally, the compound is to be described as bis(diaquooxonium)-hexaiodotellurate dihydrate, (H₇O⁺₃)₂[TeI^2?₆] · 2 H₂O. Isolated TeI^2?₆ octahedra are surrounded by a water structure which consists of disordered chains of hydrogen-bonded H₂O and H₇O⁺₃ species.     

RbFe[BP2O8(OH)]: Ein neues Borophosphat mit offen-verzweigten Vierer-Einfach-Tetraederketten

RbFe[BP₂O₈(OH)]: A New Borophosphate Containing Open-Branched Tetrahedral Vierer-Einfach Chains RbFe[BP₂O₈(OH)] is formed under mild hydrothermal conditions (T = 165–170 °C) from a mixture of RbOH_(aq), FeCl₂ · 4 H₂O, H₃BO₃ and H₃PO₄. The crystal structure of the monoclinic compound was solved by x-ray single crystal methods (space group P2₁/c, No. 14): a = 935.8(5) pm, b = 833.9(6) pm, c = 965.6(5) pm; β = 101.69(4)°; Z = 4. The anionic partial structure contains open-branched vierer-einfach chains [BP₂O₈(OH)]^4–, which are formed by alternating borate and phosphate tetrahedra sharing common corners. Fe³⁺ is in an octahedral coordination (FeO₅(OH)), while Rb⁺ is irregularly coordinated by ten oxygen-functions of neighbouring tetrahedra.