K(1+2x)Ni(1−x)Fe(2)(AsO(4))(3) (x = 0,125): un nouvel arséniate à structure de type α-CrPO(4)

A new arsenate K(1+2x)Ni(1−x)Fe(2)(AsO(4))(3) (x = 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(4)-structure type, space group Imma. It consists of a three-dimensional-framework built up from FeO(6) and Ni(0.875)□(1.25)O(6)-octa­hedra and AsO(4)-tetra­hedra 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.