Synthesis of [(Ph₄P)AgSe₄]_n. A novel one-dimensional inorganic polymer

The authors report the synthesis and structural characterization of a silver polyselenide with an unprecedented low-dimensional polymer structure. A single-crystal X-ray diffraction analysis reveals that the compound is composed of noninteracting Ph₄P^PLU cations and [Ag(Se₄)]_n^n- macroanions. The latter are infinite one-dimensional chains running parallel to the monoclinic b-axis. The basic repeating unit is a five-membered AgSe₄ ring containing the chelating Se₄^2- ligand. Preliminary examination of the charge transport and optical properties along the needle axis of the single crystals indicates wide bandgap/narrow bandwidth semiconducting behavior. A steep optical absorption threshold occurs at 384 nm suggesting a bandgap of 3.2 ev.