We report the solid-state synthesis of all eighteen layered oxide chalcogenides in the structural family π΄π2π2O
(A = K/Rb/Cs; M = Ti/V; Q = S/Se/Te), allowing the determination of trends in composition and reactivity
within the series. All materials are isostructural, crystallising in the primitive tetragonal space group π 4βπππ as
reported previously for five compounds in the series. The titanium or vanadium ions have intermediate valency
on a single crystallographic site, leading to temperature-independent paramagnetism and correlated electronic
behaviour which is influenced by the compositional variation. Furthermore, the alkali metal ions in KTi2Te2O
and RbTi2Te2O can be removed by oxidative deintercalation using H2O at room temperature to produce a new
metastable van der Waals layered phase, Ti2Te2O. During the deintercalation reaction the oxide chalcogenide
layers undergo a relative shift by (0.5, 0.5) in the ππ plane such that Ti2Te2O is body-centered with space group
πΌ4βπππ.
X-ray diffraction
,layered materials
,heteroanionic
