Crystal structure of strontium and barium acesulafame (6-methyl-4-oxo-4H-1,2,3-oxa­thia­zin-3-ide 2,2-dioxide)

Both strontium and barium acesulfames, namely poly[aqua­bis­(μ(3)-6-methyl-2,2-dioxo-1,2λ(6),3-oxa­thia­zin-4-olato)strontium(II)], [Sr(C(4)H(4)NO(4)S)(2)(H(2)O)](n), and the barium(II) analogue, [Ba(C(4)H(4)NO(4)S)(2)(H(2)O)](n), crystallize in nearly identical isotypic forms, with barium–oxygen inter­atomic distances being longer due to the larger ionic radius of the barium(II) ion. The coordination number of the metal ion is 9; the coordination polyhedra can be described as distorted capped square anti­prisms [Johnson solid J10; Johnson (1966). Can. J. Math. 18, 169–200]. The conformation of the acesulafame ions is a distorted envelope with an out-of-plane S atom. Metal and acesulfame ions are assembled into infinitive chains along the [100] axis. These chains are connected via hydrogen bonds into a three-dimensional network.