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 . It consists of a three-dimensional-framework built up from FeO and Ni□O-octa-hedra and AsO-tetra-hedra that are sharing corners and/or edges, generating tunnels running along the [010] and [001] directions in which the potassium cations are located. The proposed structural model was validated by bond-valence-sum calculations, charge-distribution (CHARDI) and Madelung energy analyses.