Crystal Structure Formation in Compounds with [Hg2]2+ Dimers

This paper describes the arrangement of cations in the structures of inorganic compounds HgVO₃, HgReO₄, Hg₂MoO₄ ( and , Hg₂Mo₂O₇, Hg₂Mo₅O₁₆, Hg₅Re₂O₁₀ (two modifications), Hg₂ReO₅, and Hg₂VO₄. To isolate crystal-forming planes and cation sublattices, it is preferable to consider the [Hg₂]²⁺ dumbbell pair as a single cation. Two types of mutual orientation of close-packed cation planes intersecting at an angle of 60° or 90° (45°) have been found. Details of three-dimensional ordering of cations and possible methods of structure modification in polymorphous transformations are discussed.