The crystal structure of a lithium–nickel molybdate, Li2Ni2Mo3O12, and the systematics of the structure type

Li2Ni2Mo3Ol2 is orthorhombic, a = 10.423 (3), b -17.525 (4), c = 5-074 (1) A, space group Pmcn with Z = 4. 2717 independent reflexions were collected and the structure was refined to an R value of 0.053. The average Mo-O and (Ni,Li)-O distances are 1.774 and 2.097 A, respectively. The close-packed sheets of O are composed of three-square-wide bands of Wells's No. 9 regular net, held together by semi-regular single chains of triangles. There are two identical sheets in the stacking sequence, and the regular and semi-regular voids between the O atoms are filled by the cations: Ni and Li occupy, in various proportions, the trigonal prism (M1), the distorted (M2) and the regular (M3) trigonal antiprisms, and Mo occupies the elongated tetrahedral voids.