Synthesis, Structure, and Electronic Properties of Sn(CN) and SnCl(CN).

A solid-state metathesis reaction between equimolar amounts of Li(CN) and SnCl revealed the formation of two new compounds, SnCl(CN) and Sn(CN). Thermal analysis of this reaction indicated that SnCl(CN) forms exothermically near 200 °C and subsequently transforms into Sn(CN) at higher temperatures. The crystal structures of both compounds are presented. According to optical measurements and band structure calculations, Sn(CN) can be considered as a semiconductor with a band gap on the order of 2 eV. The presence of Sn ions in the structure of Sn(CN) with a toroidally shaped lone pair is indicated by electron localization function calculations. The structure of Sn(CN) is shown to be related to the structures of FeS and CaC.