Two packing motifs based upon chains of edge-sharing PbI₆ octahedra

The compounds catena-poly[p-phenylenediammonium [[diiodolead(II)]-di-μ- iodo] dihydrate], {(C₆H₁₀N₂)[PbI ₄]·-2H₂O}_n, (I), and catena-poly[bis(3,5-dimethylanilinium) [[diiodolead(II)]-di-μ-iodo]], {(C₈H₁₂N)₂[PbI₄]}_n, (II), crystallize as organic-inorganic hybrids. As such, the structures consist of chains of [PbI₂]^- units extending along the c axis in (I) and along the b axis in (II). The asymmetric unit in (I) contains one Pb atom on a site of 2/m symmetry, two I atoms and a water molecule on mirror planes, and a p-phenylenediammonium molecule that sits around a site of 2/m symmetry with the C and N atoms on a mirror plane. In (II), the Pb atom is on a twofold axis and the two I atoms are on general positions. Each Pb atom is octahedrally coordinated to six I atoms, arranged as chains of edge-sharing octahedra. Both compounds undergo hydrogen-bonding interactions between the ammonium groups and the I atoms. In addition, there are hydrogen bonds between the water molecules and the ammonium groups and halides in (I), and between the ammonium groups and the ring systems in (II).