title: Disodium zinc bis-(sulfate) tetra-hydrate (zinc astrakanite) revisited.
abstract: We present a new low-temperature refinement of disodium zinc bis-(sulfate) tetra-hydrate {systematic name: poly[tetra-μ-aqua-di-μ-sulfato-zinc(II)disodium(I)]}, [Na(2)Zn(SO(4))(2)(H(2)O)(4)](n) or Zn astrakanite, which is an upgrade of previously reported data [Bukin & Nozik (1974 ▶). Zh. Strukt. Khim.15, 712-716]. The compound is part of an isostructural family containing the Mg (the original astrakanite mineral), Co and Ni species. The very regular ZnO(aqua)(4)O(sulfate)(2) octa-hedra lie on centres of symmetry, while the rather distorted NaO(aqua)(2)O(sulfate)(4) octa-hedra appear at general positions, linked into a three-dimensional network by the bridging water mol-ecules and the fully coordinated sulfate groups.
authors.forename: M Enriqueta
authors.initials: ME
authors.lastname: Díaz de Vivar
authors.forename: Sergio
authors.initials: S
authors.lastname: Baggio
authors.forename: Andrés
authors.initials: A
authors.lastname: Ibáñez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Baggio