Crystal structure of polymeric bis-(3-amino-1H-pyrazole)-cadmium diiodide

The reaction of cadmium iodide with 3-amino-pyrazole (3-apz) in ethano-lic solution leads to tautomerization of the ligand and the formation of crystals of the title compound, catena-poly[[di-iodido-cadmium(II)]-bis-(μ-3-amino-1H-pyrazole)-κ² N ²:N ³;κ² N ³:N ²], [CdI₂(C₃H₅N₃)₂] or [CdI₂(3-apz)₂] . Its asymmetric unit consists of a half of a Cd²⁺ cation, an iodide anion and a 3-apz mol-ecule. The Cd²⁺ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans-CdN₄I₂ octa-hedra, which are linked into chains by pairs of the bridging ligands. In the crystal, the ligand mol-ecules and iodide anions of neighboring chains are linked through inter-chain hydrogen bonds into a di-periodic network. The inter-molecular contacts were qu-anti-fied using Hirshfeld surface analysis and two-dimensional fingerprint plots, revealing the relative qu-anti-tative contributions of the weak inter-molecular contacts.