14215-29-3

The ternary transition-metal nitridophosphates CdP2N4 and MnP2N4 have been synthesized under high-pressure higherature conditions (5-8 GPa, 1000-1300°C) by using the multianvil technique. Cd and Mn azides can be used as the starting materials, however, with respect to safety considerations, it is much more advantageous to start from metal powders and phosphorus nitride imide, HPN2. Both nitridophosphates crystallize in a structure closely related to the megacalsilite structure type. As a result of the known issues concerning superstructures with this type of structure, TEM investigations were performed on CdP2N4, which revealed that the megacalsilite superstructure is not equally pronounced in all crystallites. By adding NH4Cl as mineralizer, single crystals were obtained that exhibit unequally pronounced superstructure reflections. Consequently, an averaged structural model was used and refined by the Rietveld method [P6322, a = 16.7197(3), c = 7.6428(2) ?, V = 1850.3(2) ?3, Rp = 0.0671, wRp = 0.0869 for CdP2N4 and P6322, a = 16.5543(2), c = 7.5058(2) ?, V = 1781.3(1) ?3, Rp = 0.0526, wRp = 0.0697 for MnP2N4]. The 31P NMR spectra exhibit four signal groups at (6.4, 4.8), 0.8, and -9.7 ppm with pronounced shoulders belonging to the same phase in an approximate area ratio of 4.8:1.1:2.0, thereby proving at least eight P sites.

Solvent free, binary cadmium azide was synthesized by the reaction of cadmium carbonate and a 24 weight% solution of HN3 in water. Cadmium azide is a colorless, crystalline powder which is highly sensitive to percussion and heat. Caution, the manipulation of Cd(N3)2 is very dangerous! The crystal structure was solved by single-crystal methods and the phase purity was verified by a Rietveld refinement (Cd(N3) 2, Pbca, no. 61; a = 7.820(2), b = 6.440(2), c = 16.073(3) A; Z = 8, 1174 independent reflections, 64 parameters, R1 = 0.022). Cadmium azide crystallizes in a new structure type. In the crystal there are edge-sharing Cd2(N3)10 double octahedrons which are further connected to other units by azide bridges. Vibrational spectroscopic investigations (Raman an IR) are discussed with respect to the crystal structure data.

The crystal structures of LiN3*;H2O (P6 3/mcm (No. 193), Z = 6; 924.01(13); 560.06(7) pm); NH 4N3 (Pmna (No. 53), Z = 4; a = 889.78(18), b = 380,67(8), c = 867.35(17) pm); Ca(N3)2 (Fddd (No. 70), Z = 8; a = 595.4(2), b = 1103.6(5), c = 1133.1(6) pm), Sr(N3)2 (Fddd(No. 70), Z = 8; a = 612.02(9), 6 = 1154.60(18), c = 1182.62(15) pm); Ba(N3)2 (P21/m (No. 11), Z = 2; a = 544.8(1), b = 439.9(1), c = 961.3(2) pm, β = 99.64(3)°) and TIN3 (I4/mcm (No. 140), Z = 2; 618.96(9); 732.71(15) pm) have been either determined for the first time or redetermined by X-ray diffraction on single crystals. The afore mentioned compounds, AN3 (A = Na, K, Rb, Cs), M(N 3)2 · 2.5 H2O (M = Mg, Zn) and the cyanamides Li2CN2, CdCN2 and CuCN2 were investigated by Raman and IR spectroscopy (KBr technique). Structural features and spectroscopic data of azides and cyanamides from this work and from literature are listed and compared.

Following our interest in binary element-nitrogen compounds we report here on the synthesis and comprehensive characterization (M.p., IR/Raman, elemental analysis, 14N/133Cd/199Hg NMR) of tri-and tetraazido cadmate and mercurate anions [E(N3)(2+n)]n- (E = Cd, Hg; n = 1, 2) in a series of [Ph4P]+ and [PNP]+ ([PNP]+ = bis(triphenylphosphine)-iminium) salts. The azide/chloride exchange in CH2Cl2 as well as the formation of tetrazolate salts in CH3CN solutions of the polyazido mercurates were investigated. Single crystal X-ray structures of all new compounds, and for comparison [Ph4P][Cd2(N3)5(H2O)], were determined. Moreover, the synthesis of anhydrous cadmium(II) azide and its DMSO adduct is presented for the first time. For a better understanding of structure and bonding in E(N3)2, [E(N3)3]- and [E(N3)4]2-, theoretical calculations at the M06-2X/aug-cc-pVDZ level were carried out.