Metal iodides in polyiodide networks: Synthesis and structure of binary metal iodide-iodine compounds stable under ambient conditions

The reaction between HgI2(C6N4H12) and HI in ethanol solution results in the binary metal iodide-iodine complexes [C6N4H13](2)(Hg2I6)(1/2)(HgI3) . 1/2 I-2, which are stable under ambient conditions. The structure consists of C6N4H13+ cations, discrete trigonal HgI3- ions, and ...Hg2I62- ... I-2 ...Hg2I62- chains in the crystallographic b direction, which are formed by I-2 molecules connecting the bridging iodines of the Hg2I62- dimers. The intra- and intermolecular I-I distances of iodine in the chain are 2.7402(15) and 3.438(1) Angstrom, respectively. The Raman spectrum of [C6N4H13](2)(Hg2I6)(1/2)(HgI3) . 1/2 I-2 confirms the interaction between the iodine molecules and Hg2I62- ions. The structure of [NH4](HgI3) . H2O, obtained during the synthesis of [C6N4H13](2)(Hg2I6)(1/2)(HgI3) . 1/2 I-2, is also reported. Crystal data for [C6N4H13](2)(Hg2I6)(1/2)(HgI3) . 1/2 I-2: a = 14.275(3) Angstrom, b = 19.721(4) Angstrom, c = 10.416(2) Angstrom, orthorhombic space group Pbam; Z = 4. Crystal data for [NH4](HgI3) . H2O: a = 8.7246(4) Angstrom, b = 9.7860(3) Angstrom, c = 11.1103(4) Angstrom, orthorhombic space group Ama2; Z = 4.