Orthorhombic La$_{3}$Ni$_{2}$O$_{7}$ Structure: A3B2C7_oF48_69_ag_g_bgl-001
| Prototype | La$_{3}$Ni$_{2}$O$_{7}$ |
| AFLOW prototype label | A3B2C7_oF48_69_ag_g_bgl-001 |
| ICSD | 93920 |
| CCDC | 1653370 |
| Pearson symbol | oF48 |
| Space group number | 69 |
| Space group symbol | $Fmmm$ |
| AFLOW prototype command |
aflow --proto=A3B2C7_oF48_69_ag_g_bgl-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak x_{3}, \allowbreak x_{4}, \allowbreak x_{5}, \allowbreak x_{6}$ |
- La$_{3}$Ni$_{2}$O$_{7-\delta}$ is a Ruddlesden-Popper compound with a bilayer NiO$_{6}$ structure. The exact structure depends on the pressure and/or oxygen deficiency. (Park, 2001; Lin, 2024)
- Under ambient pressure the fully stoichiometric compound is in the Sr$_{3}$SnO$_{7}$ structure.
- At pressures above ≈ 10$\,$GPa or when $\delta ≈ \,$0.06 it is in the current structure.
- As $\delta$ increases the system transforms into the tetragonal Sr$_{3}$Ti$_{2}$O$_{7}$ structure.
- (Sun, 2023) report
signatures
of superconductivity in this structure at 80$\,$K at pressures between 14 and 43.5$\,$GPa. - The data for this structure was taken from (Park, 2001) at ambient pressure, and the oxygen (2b) site has 4% vacancies.
- The AFLOW prototype label algorithm swaps the a and c axis compared to experiment, and moves the origin from the O I site to the La I site.
- This structure is a ternary form of the SrLa$_{2}$Sc$_{2}$O$_{7}$ structure.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{2}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}c \,\mathbf{\hat{z}}\\\mathbf{a_{3}}&=&\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (4a) | La I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (4b) | O I |
| $\mathbf{B_{3}}$ | = | $- x_{3} \, \mathbf{a}_{1}+x_{3} \, \mathbf{a}_{2}+x_{3} \, \mathbf{a}_{3}$ | = | $a x_{3} \,\mathbf{\hat{x}}$ | (8g) | La II |
| $\mathbf{B_{4}}$ | = | $x_{3} \, \mathbf{a}_{1}- x_{3} \, \mathbf{a}_{2}- x_{3} \, \mathbf{a}_{3}$ | = | $- a x_{3} \,\mathbf{\hat{x}}$ | (8g) | La II |
| $\mathbf{B_{5}}$ | = | $- x_{4} \, \mathbf{a}_{1}+x_{4} \, \mathbf{a}_{2}+x_{4} \, \mathbf{a}_{3}$ | = | $a x_{4} \,\mathbf{\hat{x}}$ | (8g) | Ni I |
| $\mathbf{B_{6}}$ | = | $x_{4} \, \mathbf{a}_{1}- x_{4} \, \mathbf{a}_{2}- x_{4} \, \mathbf{a}_{3}$ | = | $- a x_{4} \,\mathbf{\hat{x}}$ | (8g) | Ni I |
| $\mathbf{B_{7}}$ | = | $- x_{5} \, \mathbf{a}_{1}+x_{5} \, \mathbf{a}_{2}+x_{5} \, \mathbf{a}_{3}$ | = | $a x_{5} \,\mathbf{\hat{x}}$ | (8g) | O II |
| $\mathbf{B_{8}}$ | = | $x_{5} \, \mathbf{a}_{1}- x_{5} \, \mathbf{a}_{2}- x_{5} \, \mathbf{a}_{3}$ | = | $- a x_{5} \,\mathbf{\hat{x}}$ | (8g) | O II |
| $\mathbf{B_{9}}$ | = | $- \left(x_{6} - \frac{1}{2}\right) \, \mathbf{a}_{1}+x_{6} \, \mathbf{a}_{2}+x_{6} \, \mathbf{a}_{3}$ | = | $a x_{6} \,\mathbf{\hat{x}}+\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (16l) | O III |
| $\mathbf{B_{10}}$ | = | $x_{6} \, \mathbf{a}_{1}- \left(x_{6} - \frac{1}{2}\right) \, \mathbf{a}_{2}- \left(x_{6} - \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $- a \left(x_{6} - \frac{1}{2}\right) \,\mathbf{\hat{x}}+\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (16l) | O III |
| $\mathbf{B_{11}}$ | = | $\left(x_{6} + \frac{1}{2}\right) \, \mathbf{a}_{1}- x_{6} \, \mathbf{a}_{2}- x_{6} \, \mathbf{a}_{3}$ | = | $- a x_{6} \,\mathbf{\hat{x}}+\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (16l) | O III |
| $\mathbf{B_{12}}$ | = | $- x_{6} \, \mathbf{a}_{1}+\left(x_{6} + \frac{1}{2}\right) \, \mathbf{a}_{2}+\left(x_{6} + \frac{1}{2}\right) \, \mathbf{a}_{3}$ | = | $a \left(x_{6} + \frac{1}{2}\right) \,\mathbf{\hat{x}}+\frac{1}{4}b \,\mathbf{\hat{y}}+\frac{1}{4}c \,\mathbf{\hat{z}}$ | (16l) | O III |
References
- J.-C. Park, D.-K. Kim, S.-H. Byeon, and D. Kim, XANES study on Ruddlesden-Popper phase, La$_{n+1}$Ni$_{n}$O$_{3n+1}$ (n = 1, 2, and $\infty$), J. Synchrotron Rad. 8, 704–706 (2001), doi:10.1107/S0909049500015983.
- L.-F. Lin, Y. Zhang, N. Kaushal, G. Alvarez, T. A. Maier, A. Moreo, and E. Dagotto, Magnetic phase diagram of a two-orbital model for bilayer nickelates varying doping, Physical Review B 110, 195135 (2024), doi:10.1103/PhysRevB.110.195135.
- H. Sun, M. Huo, X. Hu, J. Li, Z. Liu, Y. Han, L. Tang, Z. Mao, P. Yang, B. Wang, J. Cheng, D.-X. Yao, G.-M. Zhang, and M. Wang, Signatures of superconductivity near 80 K in a nickelate under high pressure, Nature 621, 493–498 (2023), doi:10.1038/s41586-023-06408-7.
Found in
- Inorganic Crystal Structure Database. Entry 93920 (La3Ni2O7).
First cited in
- N. Anderson, M. J. Mehl, H. Eckert, S. Divilov, X. Campilongo, S. Curtarolo, The AFLOW Library of Crystallographic Prototypes: Part 5. Submitted to Computational Materials Science (2026).
Geometry files
Prototype Generator
aflow --proto=A3B2C7_oF48_69_ag_g_bgl --params=$a,b/a,c/a,x_{3},x_{4},x_{5},x_{6}$