A three‐dimensional framework of bis­[tris­(ethyl­enediamine)zinc] tetra­iodo­cadmate diiodide assisted by N—H⋯I hydrogen bonds

The title salt, Zn(C₂N₂H₈)₃]₂CdI₄]I₂, conventionally abbreviated Zn(en)₃]₂CdI₄]I₂, where en is ethyl­enediamine, contains discrete Zn(en)₃]²⁺ cations and CdI₄]^2? anions with distorted octa­hedral and nearly tetra­hedral geometries, respectively, as well as uncoordinated I^? ions. The cation and the free I^? anion lie on twofold rotation axes and the CdI₄]^2? anion lies on a axis in the space group I2d. The structure exhibits numerous weak inter‐ionic hydrogen bonds of two types, viz. N—H?I^?(free ion) and N—H?I(CdI₄]^2?), which support the resulting three‐dimensional framework.