Structural and Electronic Effect Driven Distortions in Visible Light Absorbing Polar Materials ATa₂V₂O₁₁ (A = Sr, Pb)

Complex vanadates of tantalum(V), such as ATa₂V₂O₁₁ (A = Sr, Pb), are rare and underrated materials, which have potential application domains that could be substantially expanded, mitigating the existing controversy on their atomic and electronic organization. Herein, we present a thorough structural examination combining synchrotron powder X-ray diffraction-aided distortion mode analysis with computational methods to study hettotypes of SrTa₂V₂O₁₁ (STVO) and PbTa₂V₂O₁₁ (PTVO). Being distinct from the perovskite family due to the presence of [VO₄] groups, both compounds are polar dielectric materials with certain similarities to SBT and PBT Aurivillius phases. Applying the model of anions of metallic matrices to the analysis of electron localization functions calculated on top of as-established equilibrium structures helps retrace the effects in the Sr and Pb surroundings on the respective crystal packings of STVO and PTVO.