Low temperature synthesis and characterization of SnTa2O6

Sn(II)Ta2O6 is well known as the mineral Thoreaulite, but attempts to prepare it by direct combination of SnO and Ta2O5 fail. SnTa2O6 has now been synthesized by reacting SnCl2 with KTaO3 at 673 K under an inert atmosphere. Although a reported structure determination of SnTa2O6 indicated an acentric space group, our second harmonic generation (SHG) studies indicate that SnTa2O6 is centrosymmetric as is the case for isostructural SnNb2O6.