Hexa­aqua­bis­[3,5-bis­(hy­droxy­imino)-1-methyl-2,4,6-trioxo­cyclo­hexa­nido-κ²N³,O⁴]barium tetrahydrate

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.