ROOM-TEMPERATURE SYNTHESIS OF SN2P2S6

Twenty-nanometer particles of Sn2P2S6 are prepared at room temperature (RT) via a metathesis reaction in aqueous media. Mossbauer and Raman spectroscopy and X-ray diffraction characterization of these powders a ccord with data on Sn2P2S6 synthesized at high temperature (HT). The p hase transition and second harmonic generation known to exist in the H T form were not detected in the RT variant, suggesting a critical part icle size >20 nm for the occurrence of polar order in Sn2P2S6. It is a rgued that thermal enhancement of the metathesis reaction and growth k inetics should lead to larger, ferroelectric Sn2P2S6 crystallites. (C) 1997 Academic Press.