A structural comparison of Te6+, Mo6+, and W6+ compositions with the A2BB′O6 stoichiometry will be presented. We show that much like d0 Mo6+- and W6+-containing perovskites, p0 Te6+-containing compositions are strongly affected by the tolerance factor and identities of the A- and B-cations. Additionally, crystal structures for five A2BTeO6 (A = Ca2+, Sr2+, or Ba2+; B = Zn2+ or Cd2+) perovskites were determined via powder diffraction and their vibronic and electronic structures were probed via infrared and diffuse reflectance spectroscopy. The new structural information we report coupled with a thorough review of relevant literature demonstrates that Te6+, with its sigma bonding preference and lack of allowed orbital mixing, gives rise to additional structure types that are not commonly observed in the Mo6+- or W6+- analogues. Analysis of double perovskites containing the hexavalent cations comparing the tolerance factor to the difference in ionic radii of the cations with octahedral coordination will be presented. Additionally, examination of the Coulombic repulsions between the B and Te6+ cations plotted as a function of difference in the twelve- and seven-coordinate ionic radii for the A- and B-cations respectively provides new insight on why A2BTeO6 and A2BWO6 (A = B = Sr2+ or Ba2+) adopt perovskite structures with non-cooperative octahedral tilting distortions, while cooperative octahedral distortions are observed when the A and B sites are occupied by smaller cations like Ca2+ and Cd2+.

Comparison of the crystal chemistry of tellurium (VI)-, molybdenum (VI)-, and tungsten (VI)-containing double perovskites and related materials

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.