<i>catena</i>-Poly[[[diaquacadmium(II)]bis[μ-2-(pyridinium-1-yl)butanedioato]-κ<sup>2</sup><i>O</i><sup>1</sup>:<i>O</i><sup>4</sup>;κ<sup>2</sup><i>O</i><sup>4</sup>:<i>O</i><sup>1</sup>] tetrahydrate], a polymeric chain structure
Acta crystallographica. Section E