Dy2(SO3)2(SO4)(H2O)2: the first lanthanide mixed sulfate–sulfite inorganic compound

The first lanthanide mixed sulfate–sulfite inorganic coordination polymer, poly[diaqua-μ4-sulfato-di-μ4-sulfito-didysprosium(III)], [Dy2(SO3)2(SO4)(H2O)2]n, has been obtained, in which both sulfate and sulfite groups originate from the disproportionation of S2O32− under hydro­thermal and weakly acidic conditions. The crystal structure of the title compound exhibits a three-dimensional framework. The DyIII ion is surrounded by eight O atoms from one water mol­ecule and two sulfate and five sulfite groups. These DyO8 polyhedra have two shared edges and form an infinite zigzag Dy—O chain. In the bc plane, neighbouring chains are integrated through SO3 trigonal pyramids, forming a two-dimensional sheet. Along the a-axial direction, the sulfate group, with the central S atom lying on a twofold axis, links adjacent two-dimensional sheets via two S—O—Dy connections, thus generating the three-dimensional framework.