Validating the model of a (3 + 1)-dimensional incommensurately modulated structure as generator of a family of compounds for the Eu₂(MoO₄)₃ scheelite structure

Abstract

The previously proposed model postulating that the incommensurately modulated KNd(MoO₄)₂ structure can act as a generator of the scheelite family members is validated here by refining the crystal structure of europium molybdate, Eu₂(MoO₄)₃. The initial structural model was derived from the superspace characteristics of KNd(MoO₄)₂ and the predicted parameters used in the simulation of Eu₂(WO₄)₃. The refinement was performed using both superspace and traditional supercell approaches in superspace group I2/b(αβ0)00 and space group A 2/a, respectively. The results obtained by both approaches are in excellent agreement and coincide with those reported in the literature.

Keywords:

• scheelite compounds
• superspace approach
• supercell
• crystal structure

Acknowledgements

The support for this work provided by the Swiss National Science Foundation (Grant 20-113605) is gratefully acknowledged. V.A. Morozov is grateful to the Russian Foundation for Basic Research (Grant 08-03-00593) for financial support. We would like to thank Lukáš Palatinus for useful discussions and suggestions and the Swiss-Norwegian beamline for the provision of synchrotron radiation facilities.