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Abstract

Sodium may be topotactically inserted into the perovskite layers (under thermodynamic control) or the rock-salt layers (under kinetic control) of the cation-deficient n = 2 Ruddlesden-Popper oxysulfides Ln2Ti2O5S2 with concomitant reduction of TiIV.

Room temperature oxidative intercalation with chalcogen hydrides: Two-step method for the formation of alkali-metal chalcogenide arrays within layered perovskites

“…A 2 F 2 Fe 2 OCh 2 (A = Sr, Ba; Ch = S, Se) compounds, for instance, display a frustrated antiferromagnetic checkerboard lattice [42]. Other alkali-metal containing oxysulfides have been prepared topochemically; Y 2 Ti 2 O 5 S 2 for example has been reductively intercalated with Li, Na and K [34][35][36][37]. The interlayer coordination geometry for K in KY 2 Ti 2 O 5 S 2 is similar to that seen for Rb in Rb-S (Fig.…”

“…Many such oxychalcogenides are already known including those that exhibit interesting magnetic and electronic properties [31][32][33][34][35][36][37][38][39][40][41][42]. The series Sr 2 MnO 2 Cu 2mÀd S m+1 (m = 1, 2, and 3), for example, contains copper-sulfide layers of varying thicknesses (m) and is found to exhibit metamagnetic behavior [32].…”

Crystal structure and electrical properties of the mixed valent titanium oxysulfide Sm2Ti2S2O4.5

“…The oxide layer is of ReO 3 type with empty sites, and contains Ti(IV) cations only. By filling the voids with Cu atoms we have attempted to reduce the Ti atoms planning to induce a metal-insulator transition in these phases; intercalation of alkali metals into these phases has been already performed with success [10]. Our attempt was unsuccessful but we have obtained a new phase Sm 2 Ti 2 S 2 O 4.5 that contains both Ti(III) and Ti(IV).…”

“…and/or interesting structural features (anionic segregation [3], layered structures [4,5]). Among all systems, the rare-earth titanium oxychalcogenide system has been the most studied and several compounds have been characterized, as exemplified for instance by La 8 Ti 10 [9]. In most cases, titanium adopts the +IV oxidation state, but it was also found with the +III oxidation state or in a mixed valence state.…”

Y2Ti2O5S2 as a high performance anode material for Li ion batteries

“…1a, the crystal structure of YTOS consists of an alternating stacking of Ti 2 O 5 double layer units with corner shared TiO 5 pyramids and Y 2 S 2 layer units [4]. The crystal chemistry and electronic structure of YTOS intercalated with Li + and Na + have been previously studied [5][6][7]. Both Li + ions and Na + ions are located within Ti 2 O 5 layer units.…”