The crystal structure of Ni 4 V 3 O 10 was solved in the P 4/n space group with powder Xray diffraction data from a sample made by the ball milling procedure. The unit cell of Ni 4 V 3 O 10 contains two formula units and is shown in Fig. . The structure includes octahedral, tetrahedral, and square pyramidal cation-oxygen coordination geometries. While nickel ions are present only on octahedral sites, the vanadium ions occupy every cation site. The polyhedra form a set of three distorted planes normal to the c-axis and the structure contains a checkerboard pattern resembling a rock-salt structure.