ChemInform Abstract: Synthesis and Properties of Nanocrystalline π-SnS - A New Cubic Phase of Tin Sulfide.

Cubic π-SnS nanoparticles are precipitated by melting tin ethylxanthate as precursor and octadecylamine (120 °C, 30 min) after which (Tms)2NH is added under further heating to 220 °C (2 h) before being transferred to a 1:1 mixture of CHCl3 and MeOH. Alternatively, SnCl2 mixed with oleylamine is heated to 120 °C before (Tms)2NH is added and further heated to 150 °C (30 min) upon which a solution of S in oleylamine (150 °C) is added to yield the SnS nanoparticles after 5 min. Shape control of the nanoparticles is achieved by the variation of synthetic parameters resulting in cubic (the common shape), rhombic dodecahedral, and tetrahedral morphologies. Powder XRD confirms the proposed structural model and yields a lattice parameter a = 11.595 Å. Raman spectroscopy shows a substantial shift towards higher energies and peak splitting for π-SnS. An indirect band gap of 1.53 eV is determined from optical absorption which agrees well with DFT calculations. DFT total energy calculations show that π-SnS is energetically similar to α-SnS and significantly more stable than the hypothetical ideal rocksalt structure of SnS.