Sodium intercalation into the n=2 Ruddlesden-Popper type host Y2Ti2O5S2: Synthesis, structure, and properties of alpha-NaxY2Ti2O5S2 (0 < x <= 1) - Clarke, S; Denis, S; Rutt, O; Hill, T; Hayward, M; Hyett, G; Gal, Z (CHEMISTRY OF MATERIALS, 2003)