Crystal structure of polymeric bis-(3-amino-1 H -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-1 H -pyrazole)-κ 2 N 2 : N 3 ;κ 2 N 3 : N 2 ], [CdI 2 (C 3 H 5 N 3 ) 2 ] n or [CdI 2 (3-apz) 2 ] n . Its asymmetric unit consists of a half of a Cd 2+ cation, an iodide anion and a 3-apz mol-ecule. The Cd 2+ cations are coordinated by two iodide anions and two 3-apz ligands, generating trans -CdN 4 I 2 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.