Text this: The crystal structure of poly[2-(4-carboxypyridin-3-yl)terephthalpoly[diaqua-(μ4-2-(6-carboxylatopyridin-3-yl)terephthalato-κ5O,N:O′:O″,O‴)]) cadmium(II)] dihydrate, C28H20Cd3N2O16