The luminescent semiconductor Pb₇I₆(CN₂)₄

The development of new compounds in the domain of metal dinitridocarbonates is most efficiently performed via solid-state metathesis or simply by addition reactions. Our discovery of Pb₇I₆(CN₂)₄ is the result of a solid-state reaction of PbCN₂ with PbI₂ at 420 °C. Its crystal structure was solved and refined from X-ray diffraction data based on a single crystal with the space group P6₃/mmc. The crystal structure is based on a network of lead tetrahedra, lead trigonal bipyramids and lead octahedra interconnected by [NCN]^2- and iodide. Properties of the material were investigated by diffuse reflection measurement, photoluminescence measurements, and electronic band structure calculations demonstrating that this material is a semiconductor.