Hexa-aqua-bis-[3,5-bis-(hy-droxy-imino)-1-methyl-2,4,6-trioxo-cyclo-hexa-nido-κ(2) N (3),O (4)]barium tetrahydrate.

In the title compound, [Ba(C7H5N2O5)2(H2O)6]·4H2O, the Ba(2+) cation lies on a twofold rotation axis and is ten-coordinated by two 3,5-bis-(hy-droxy-imino)-1-methyl-2,4,6-trioxo-cyclo-hexa-n-ide oxo O atoms [Ba-O = 2.8715 (17) Å], two hy-droxy-imino N atoms [Ba-N = 3.036 (2) Å], and six water mol-ecules [Ba-O = 2.

catena-Poly[ammonium [aqua-bis-(μ-2,3,5,6-tetra-oxo-4-nitro-pyridin-4-ido)argentate(I)]].

In the title compound, {(NH4)[Ag(C5HN2O6)2(H2O)]} n , the Ag(I) cation is seven-coordinated and is surrounded by four oxo O atoms of the 2,3,5,6-tetra-oxo-4-nitro-pyridin-4-ide species [Ag-O = 2.3848 (19), 2.4931 (18), 2.