trans-Bis[4-amino-N-(pyrimidin-2-yl)benzene-sulfonamidato]dipyridine-cobalt(II) hemihydrate.

The asymmeric unit of the title compound, [Co(C10H9N4O2S)2(C5H5N)2]·0.5H2O, contains the distorted octa­hedral trans-[Co(sdz)2(py)2] (sdz is the sulfadiazine anion and py is pyridine) complex mol­ecule and a half-mol­ecule of water, which lies on a twofold rotation axis. A three-dimensional network is generated by N—H⋯O and O—H⋯O hydrogen bonds between the complex and the water mol­ecules.