O2-LiCoO$_{2}$ Structure: ABC2_hP8_186_b_b_ab-001
| Prototype | CoLiO$_{2}$ |
| AFLOW prototype label | ABC2_hP8_186_b_b_ab-001 |
| ICSD | none |
| Pearson symbol | hP8 |
| Space group number | 186 |
| Space group symbol | $P6_3mc$ |
| AFLOW prototype command |
aflow --proto=ABC2_hP8_186_b_b_ab-001
--params=$a, \allowbreak c/a, \allowbreak z_{1}, \allowbreak z_{2}, \allowbreak z_{3}, \allowbreak z_{4}$ |
- LiCoO$_{2}$ structures are defined by the stacking arrangement of the edge-shared CoO$_{6}$ octahedra. In addition, the O3 and O4 structures may have stacking faults. (Yabuuchi, 2013) prepared all of these structures by treating
OP4
-LiNaCo$_{2}$O$_{4}$ using ion-exchange in aqueous media.- In O2-LiCoO$_{2}$ (this structure) the octahedra are stacked in an alternating cubic/hexagonal arrangement.
- In O3-LiCoO$_{3}$ the octahedra are stacked in a cubic arrangement, taking on the $\alpha$–NaFeO$_{2}$ structure.
- In O4-LiCoO$_{2}$ the octahedra alternate between O2 and O4.
- (Delmas, 1982) give the composition of this sample as Li$_{0.93}$CoO$_{1.96}$. They state that the system is in space group $P3m1$ #156, but the coordinates they give imply that all of the lithium and cobalt atoms are in equivalent positions, and the space group becomes $P6_{3}mc$ #186.
- Space group $P6_{3}mc$ #186 does not specify the origin of the $z$-coordinate. We fix it here by setting $z_{2} = 0$.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{2}a \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $z_{1} \, \mathbf{a}_{3}$ | = | $c z_{1} \,\mathbf{\hat{z}}$ | (2a) | O I |
| $\mathbf{B_{2}}$ | = | $\left(z_{1} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $c \left(z_{1} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (2a) | O I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{2} \,\mathbf{\hat{z}}$ | (2b) | Co I |
| $\mathbf{B_{4}}$ | = | $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}+\left(z_{2} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c \left(z_{2} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (2b) | Co I |
| $\mathbf{B_{5}}$ | = | $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{3} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{3} \,\mathbf{\hat{z}}$ | (2b) | Li I |
| $\mathbf{B_{6}}$ | = | $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}+\left(z_{3} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c \left(z_{3} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (2b) | Li I |
| $\mathbf{B_{7}}$ | = | $\frac{1}{3} \, \mathbf{a}_{1}+\frac{2}{3} \, \mathbf{a}_{2}+z_{4} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c z_{4} \,\mathbf{\hat{z}}$ | (2b) | O II |
| $\mathbf{B_{8}}$ | = | $\frac{2}{3} \, \mathbf{a}_{1}+\frac{1}{3} \, \mathbf{a}_{2}+\left(z_{4} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+c \left(z_{4} + \frac{1}{2}\right) \,\mathbf{\hat{z}}$ | (2b) | O II |
References
- C. Delmas, J.-J. Braconnier, and P. Hagenmuller, A new variety of LiCoO$_{2}$ with an unusual oxygen packing obtained by exchange reaction, Mater. Res. Bull. 17, 117–123 (1982), doi:10.1016/0025-5408(82)90192-1.
Found in
- N. Yabuuchi, Y. Kawamoto, R. Hara, T. Ishigaki, A. Hoshikawa, M. Yonemura, T. Kamiyama, and S. Komaba, A Comparative Study of LiCoO$_{2}$ Polymorphs: Structural and Electrochemical Characterization of O2-, O3-, and O4-type Phases, Inorg. Chem. 52, 9131–9142 (2013), doi:10.1021/ic4013922.
Prototype Generator
aflow --proto=ABC2_hP8_186_b_b_ab --params=$a,c/a,z_{1},z_{2},z_{3},z_{4}$