Rhombohedral Delafossite (CuFeO$_{2}$) Structure: ABC2_hR4_166_a_b_c-004
| Prototype | CuFeO$_{2}$ |
| AFLOW prototype label | ABC2_hR4_166_a_b_c-004 |
| Mineral name | delafossite |
| ICSD | 31918 |
| Pearson symbol | hR4 |
| Space group number | 166 |
| Space group symbol | $R\overline{3}m$ |
| AFLOW prototype command |
aflow --proto=ABC2_hR4_166_a_b_c-004
--params=$a, \allowbreak c/a, \allowbreak x_{3}$ |
Other compounds with this structure
AgAlO$_{2}$, AgCoO$_{2}$, AgCrO$_{2}$, AgFeO$_{2}$, AgGaO$_{2}$, AgInO$_{2}$, AgNiO$_{2}$, AgRhO$_{2}$, AgScO$_{2}$, AgTlO$_{2}$, CuAlO$_{2}$, CuCoO$_{2}$, CuCrO$_{2}$, CuEuO$_{2}$, CuGaO$_{2}$, CuInO$_{2}$, CuLaO$_{2}$, CuPrO$_{2}$, CuRhO$_{2}$, CuScO$_{2}$, CuYO$_{2}$, NiLaO$_{2}$, NiPrO$_{2}$, PdCoO$_{2}$, PdCrO$_{2}$, PdRhO$_{2}$, PtCoO$_{2}$
- Delafossite appears in two forms which differ in the stacking of the layers: rhombohedral, shown here, and hexagonal, prototype CuAlO$_{2}$. Most of the structures found in the hexagonal phase can also be found in the rhombohedral structure (Marquardt, 2006).
- Rhombohedral delafossite has the same AFLOW label, ABC2_hR4_166_a_b_c, as caswellsilverite CrNaS$_{2}$, $F5_{1}$ and $\alpha$–NaFeO$_{2}$.
- The difference in the internal parameter $z_{3}$ between CuFeO$_{2}$ and CrNaS$_{2}$ causes a large change in the bonding of the two crystals, so we present them as different structures.
- The structures are generated by the same symmetry operations with different sets of parameters (
--params) specified in their corresponding CIF files. - Hexagonal settings of this structure can be obtained with the option
--hex.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{\sqrt{3}}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&- \frac{1}{2}a \,\mathbf{\hat{x}}- \frac{\sqrt{3}}{6}a \,\mathbf{\hat{y}}+\frac{1}{3}c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (1a) | Cu I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}c \,\mathbf{\hat{z}}$ | (1b) | Fe I |
| $\mathbf{B_{3}}$ | = | $x_{3} \, \mathbf{a}_{1}+x_{3} \, \mathbf{a}_{2}+x_{3} \, \mathbf{a}_{3}$ | = | $c x_{3} \,\mathbf{\hat{z}}$ | (2c) | O I |
| $\mathbf{B_{4}}$ | = | $- x_{3} \, \mathbf{a}_{1}- x_{3} \, \mathbf{a}_{2}- x_{3} \, \mathbf{a}_{3}$ | = | $- c x_{3} \,\mathbf{\hat{z}}$ | (2c) | O I |
References
- C. T. Prewitt, R. D. Shannon, and D. B. Rogers, Chemistry of noble metal oxides. II. Crystal structures of platinum cobalt dioxide, palladium cobalt dioxide, coppper iron dioxide, and silver iron dioxide, Inorg. Chem. 10, 719–723 (1971), doi:10.1021/ic50098a012.
Found in
- M. A. Marquardt, N. A. Ashmore, and D. P. Cann, Crystal chemistry and electrical properties of the delafossite structure, Thin Solid Films 496, 146–156 (2006), doi:10.1016/j.tsf.2005.08.316.
Prototype Generator
aflow --proto=ABC2_hR4_166_a_b_c --params=$a,c/a,x_{3}$