Structures of bis(2-thiobarbiturato-O)tetraaquamagnesium and catena-[(μ2-2-thiobarbiturato-O,O)(2-thiobarbiturato-O) bis(μ2-aqua)diaquastrontium] monohydrate

The crystal structures of bis(2-thiobarbiturato-O)tetraaquamagnesium Mg(H2O)(4)(HTBA-O)(2) I and catena-[(mu(2)-2-thiobarbiturato-O,O)(2-thiobarbiturato-O)bis(mu(2)-aqua)diaquastrontium] monohydrate catena-[Sr(mu(2)-H2O)(2)(H2O)(2)(mu(2)-HTBA-O,O)(HBTA-O)] (n) center dot nH(2)O (II), where H(2)TBA is 2-thiobarbituric acid C4H4N2O2S, have been determined. Crystal data for a=6.7598(2) , b = 7.6060(2) , c = 8.5797(2) , alpha = 79.822(2)A degrees, beta = 76.622(1)A degrees, gamma = 69.124(1)A degrees, V = 398.82(2) (3), space group P , Z = 1; for II: a = 20.8499(4) , b = 19.2649(5) , c = 4.14007(9) , beta = 92.023(2)A degrees, V = 1661.91(7) (3), space group P2(1)/n, Z = 4. The Mg2+ ion in I is bonded to six O atoms of two HTBA(-) ions and four water molecules that form a nearly regular octahedron. Each Sr2+ ion in II is coordinated to three oxygen atoms of three HTBA(-) ions and six water molecules that form an almost ideal tricapped trigonal prism. These polyhedra share edges to form infinite chains. Intermolecular hydrogen bonds create layered structures of I and II.