Ln2Ti2S2O5 (Ln = Nd, Pr, Sm): a novel series of defective Ruddlesden–Popper phases

Abstract

The reaction of Nd₂S₂O, TiS₂ and S at 1000 °C and subsequent chemical transport with I₂ yields the new crystalline layered oxysulfide Nd₂Ti₂S₂O₅ that possesses a defective Sr₃Ti₂O₇ structure whose cuboctahedral sites within the double-perovskite layers are empty; Nd₂Ti₂S₂O₅ is paramagnetic and semiconducting; the synthesis of the isostructural compounds Pr₂Ti₂S₂O₅ and Sm₂Ti₂S₂O₅ is also reported.