Synthesis of ditin hexathiophosphate Sn2P2S6 by low-energy ball-milling and monomode microwave

High- or low-energy mechanochemistry is frequently used to synthesize chemical compounds. The present work is devoted to the possible synthesis of ditin hexathiodiphosphate Sn2P2S6 by low-energy ball-milling: first, directly from its atomic components, second, by ball-milling followed by a microwave treatment. Stoichiometric ratio powders were milled by means of 10 steel balls (2.0 g each) under ambient atmosphere for 80 h or so. Afterwards, the samples were studied by X-ray spectroscopy, energy dispersive X-ray spectroscopy, IR and DSC. The resulting diffraction patterns showed the formation of the desired compound. The ball-milled powder was also studied by transmission electron microscopy which revealed its ferroelectric character. Some previous confusing conclusions about the various crystalline forms of Sn2P2S6 are re-examined. With Mn, Fe, Ni or In instead of Sn, no hexathiodiphosphates were formed through direct ball-milling.