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arXiv · 2109.14098

Anionic Ordering in Pb$_2$Ti$_4$O$_9$F$_2$ Revisited by Nuclear Magnetic Resonance and Density Functional Theory

Kengo Oka·Tom Ichibha·Daichi Kato·Yasuto Noda·Yusuke Tominaga·Kosei Yamada·Mitsunobu Iwasaki andNaoki Noma·Kenta Hongo·Ryo Maezono·Fernando A. Reboredo
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Abstract

A combination of $^{19}$F magic angle spinning (MAS) nuclear magnetic resonance (NMR) and density functional theory (DFT) were used to study the ordering of F atoms in Pb$_2$Ti$_4$O$_9$F$_2$. This analysis revealed that F atoms predominantly occupy two of the six available inequivalent sites in a ratio of 73:27. DFT-based calculations explained the preference of F occupation on these sites and quantitatively reproduced the experimental occupation ratio, independent of the choice of functional. We concluded that the Pb atom's 6$s^2$ lone pair may play a role ($\sim$0.1 eV/f.u.) in determining the majority and minority F occupation sites with partial density of states and crystal orbital Hamiltonian population analyses applied to the DFT wave functions.

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Kengo Oka, Tom Ichibha, Daichi Kato, Yasuto Noda, Yusuke Tominaga, Kosei Yamada, Mitsunobu Iwasaki andNaoki Noma, Kenta Hongo, Ryo Maezono, Fernando A. Reboredo. 2021-09-28. Anionic Ordering in Pb$_2$Ti$_4$O$_9$F$_2$ Revisited by Nuclear Magnetic Resonance and Density Functional Theory. https://doi.org/10.1039/d2dt00839d

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