The solid solution KNi0.93FeII0.07FeIII(PO4)2{potassium [nickel(II)/iron(II)] iron(III) bis(orthophosphate)} has been prepared by the flux method. The compound shows a new type of structure for a phosphate with the general compositionMIMIIMIII(PO4)2. The framework is formed by [(Ni/Fe)O6] polyhedra [Fe site occupancy = 0.069 (14)] linkedviashared oxygen vertices forming acis-like parallel chain stretching alongaand [FeO5] polyhedra (located on alternate sides of the chains) connectedviatwo types of PO4groups into a three-dimensional structure. The K atoms are disordered between two sites, denoted K1Aand K1B, with occupancies of 0.930 (9) and 0.070 (9), respectively, and reside inside channels along theaaxis. Calculations of the Voronoi–Dirichlet polyhedra of the K atoms give a coordination scheme for K1Aof [9 + 3] and for K1Bof [10 + 2]. The most remarkable feature of the structure is the splitting of the K-atom site and the population of the K1Aand K1Bpositions due to substitution of Ni by Fe in the (Ni/Fe) position.