Hexaaquabis[3,5-bis(hydroxyimino)- 1-methyl-2,4,6-trioxocyclohexanido- j2N3,O4]barium tetrahydrate

R factor = 0.018; wR factor = 0.048; data-to-parameter ratio = 10.9. In the title compound, [Ba(C7H5N2O5)2(H2O)6]4H2O, the Ba2+ cation lies on a twofold rotation axis and is ten-coordinated by two 3,5-bis(hydroxyimino)-1-methyl-2,4,6-trioxocyclohexanide oxo O atoms [Ba—O = 2.8715 (17) Å], two hydroxyimino N atoms [Ba—N = 3.036 (2) Å], and six water molecules [Ba—O = 2.847 (2), 2.848 (2), and 2.880 (2) Å]. The 3,5-bis(hydroxyimino)-1-methyl-2,4,6-trioxocyclohexanide monoanions act in a bidentate chelating manner, coordinating through an N atom of the non-deprotonated hydroxyimino group and an O atom of the neighboring oxo group. Two lattice water molecules are located in the cavities of the framework and are involved in hydrogen bonding to O atoms of one of the coordinating water molecules and the O atom of a keto group of the ligand. As a result, a three-dimensional network is formed. Related literature For the synthesis and crystal structure of sodium 3,5-bis(hy-droxyimino)-1-methyl-2,4,6- trioxocyclohexanide, see: Koval-chukova et al. (2012). For related structures of metal complexes with 1,2-benzo(naphto)quinone-1-oximes, see