Text this: Poly[aqua[μ2-1,4-bis(imidazol-1-ylmethyl)benzene-κ2N3:N3′](μ2-5-hydroxybenzene-1,3-dicarboxylato-κ4O1,O1′:O3,O3′)cadmium(II)], a twofold interpenetrated CdSO4-like metal–organic polymer