An arsenate with the α-CrPO structure type, NaCaNiAl(AsO) (x = 0.23): crystal structure, charge-distribution and bond-valence-sum analyses.

Since the discovery of electrochemically active LiFePO, materials with tunnel and layered structures built up of transition metals and polyanions have become the subject of much research. A new quaternary arsenate, sodium calcium trinickel aluminium triarsenate, NaCaNiAl(AsO) (x = 0.23), was synthesized using the flux method in air at 1023 K and its crystal structure was determined from single-crystal X-ray diffraction (XRD) data.

K Ni Fe(AsO) ( = 0,125): un nouvel arséniate à structure de type α-CrPO.

A new arsenate K Ni Fe(AsO) ( = 1/8) {potassium nickel diiron(III) tris-[arsenate(V)]} was synthesized using a flux method and its crystal structure was determined from single-crystal X-ray diffraction data. This material was also characterized by qualitative energy dispersive X-ray spectroscopy (EDS) analysis. The crystal structure belongs to the α-CrPO-structure type, space group .

4-Aza-niumyl-2,2,6,6-tetra-methyl-piperidin-1-ium dinitrate.

In the crystal structure of the title salt, C9H22N2 (2+)·2NO3 (-), the piperidine ring of the dication adopts a chair conformation and the orientation of the C-NH3 bond is equatorial. The ions are linked by normal and bifurcated N-H⋯O hydrogen bonds in R 2 (2)(6), two R 4 (2)(8) and R 3 (4)(14) graf-set motifs, generating a three-dimensional network.

AgNi3(PO4)(HPO4)2: an alluaudite-like structure.

The new title phosphate, silver trinickel phosphate bis(hydrogenphosphate), has been synthesized by the hydrothermal method. It has an alluaudite-like structure but shows some differences owing to the presence of the H atoms. The structure is isomorphous with the compounds of general formula AM(3)(XO(4))(HXO(4))(2) (A is Na or Ag, M is Co, Zn or Mn, and X is As or P), with the Ag atom, one Ni atom and one P atom lying on twofold axes.