Electrochemical synthesis of a pseudo-two-dimensional polytelluride containing Te2−12 anions: structure of [(C2H5)4N]2Te12

Abstract

An unusual pseudo-two-dimensional polytelluride built up from Te2−12 anions was synthesized electrochemically from the cathodic dissolution reaction of an SbTe10 alloy electrode in an ethylenediamine solution of tetraethylammonium iodide, and represents the largest homoatomic polychacogenide anion characterized to date. The compound [(C2H5)4N]2Te12 crystallizes in the acentric monoclinic space group Pn (No. 7) with lattice constants of a = 7.934(1), b = 17.453(8) and c = 13.514(1) Å, β = 104.671(10)° and V = 1810.4(7) Å3, with Z = 2 and R(Rw) = 0.036(0.047). The structure consists of puckered Te122− chains, with internal Te-Te distances of 2.713(2)–2.881(2) Å, loosely bound into infinite two-dimensional sheets via many Te-Te interactions in the range of 3.144(2)–3.504(2) Å. These distances are somewhat shorter than the comparable interchain (2.835(2) Å) and intrachain (3.495(3) Å) Te-Te distances in elemental Te. The complete structure consists of these tellurium layers separated in the crystallographic b direction by layers of tetraethylammonium cations.