FeLiO$_{2}$ exhibits a wide variety of structures, with the exact structure present depends on thermodynamic effects, preparation methods, and charge/discharge history.
We follow the nomenclature of (Kanno, 1996), where appropriate, with modifications found in (Tabuchi, 1995) and (Abdel-Ghany, 2012). The following list of structures is no doubt incomplete:
$\alpha$–LiFeO$_{2}$ is in the cubic rock salt ($B1$) structure, with lithium and iron randomly placed on the sodium site and oxygen on the chlorine site. It is synthesized at temperatures above 600°C.
$\beta$–LiFeO$_{2}$ is a tetragonal distortion of $\alpha$–LiFeO$_{2}$ with the lithium and iron atoms still randomly placed on their sublattice (we denote this site as Fe).
$\beta'$–LiFeO$_{2}$ is monoclinic and transforms to $\gamma$–LiFeO$_{2}$ near room temperature. This is likely the phase (Kanno, 1996) refers to as $\beta$–LiFeO$_{2}$.
$\gamma$–LiFeO$_{2}$ (this structure) is created by low-temperature synthesis below 500°C and can be considered as an ordered version of $\alpha$–LiFeO$_{2}$, with a doubled unit cell.
o-LiFeO$_{2}$ is orthorhombic, produced by an ion exchange interaction. It is (meta)-stable below 400°C, transforming to $\alpha$–LiFeO$_{2}$ above 600°C.
For $\gamma$–FeLiO$_{2}$ we use the data taken by (Barré, 2009) at 25°.
$\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{1}{4}a \,\mathbf{\hat{y}}- c \left(z_{3} - \frac{1}{4}\right) \,\mathbf{\hat{z}}$
(8e)
O I
References
M. Barré and M. Catti, Neutron diffraction study of the β' and γ phases of LiFeO$_{2}$, J. Solid State Chem. 182, 2549–2554 (2009), doi:10.1016/j.jssc.2009.06.029.
R. Kanno, T. Shirane, Y. Kawamoto, Y. Takeda, M. Takano, M. Ohashi, and Y. Yamaguchi, Synthesis, Structure, and Electrochemical Properties of a New Lithium Iron Oxide, LiFeO$_{2}$, with a Corrugated Layer Structure, J. Electrochem. Soc. 143, 2435–2442 (1996), doi:10.1149/1.1837027.
M. Tabuchi, K. Ado, H. Sakaebe, C. Masquelier, H. Kageyama, and O. Nakamura, Preparation of AFeO$_{2}$ (A = Li, Na) by hydrothermal method, Solid State Ionics 79, 220–226 (1995), doi:10.1016/0167-2738(95)00065-E.
A. E. Abdel-Ghany, A. Mauger, H. Groult, K. Zaghib, and C. M. Julien, Structural properties and electrochemistry of α-LiFeO$_{2}$, J. Power Sources 197, 285–291 (2012), doi:10.1016/j.jpowsour.2011.09.054.
First cited in
H. Eckert, S. Divilov, M. J. Mehl, D. Hicks, A. C. Zettel, M. Esters, X. Campilongo, and S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 4, Comp. Mat. Sci. 240, 112988 (2024). (doi=10.1016/j.commatsci.2021.110450)