Class-II MV YBaFe$_{2}$O$_{5}$ Structure: AB2C5D_oP9_47_a_l_gjk_b-001
| Prototype | BaFe$_{2}$O$_{5}$Y |
| AFLOW prototype label | AB2C5D_oP9_47_a_l_gjk_b-001 |
| ICSD | 281205 |
| CCDC | 1721779 |
| Pearson symbol | oP9 |
| Space group number | 47 |
| Space group symbol | $Pmmm$ |
| AFLOW prototype command |
aflow --proto=AB2C5D_oP9_47_a_l_gjk_b-001
--params=$a, \allowbreak b/a, \allowbreak c/a, \allowbreak x_{4}, \allowbreak x_{5}, \allowbreak x_{6}$ |
Other compounds with this structure
EuBaCo$_{2}$O$_{5}$, EuBaFe$_{2}$O$_{5}$, GdBaFe$_{2}$O$_{5}$, NdBaFe$_{2}$O$_{5}$, TbBaFe$_{2}$O$_{5}$
- YBaFe$_{2}$O$_{5}$ is a mixed-valence compound which undergoes several magnetic transitions as it cools (Woodward, 2003):
- At high temperatures it is characterized as a Class-III MV (mixed valence) paramagnetic compound with equivalent iron atoms. It exists in a double perovskite structure in tetragonal space group $P4/mmm$ #123. This appears to be related to YBaCuFeO$_{5}$, but we have no experimental confirmation of that.
- Below 430K the system distorts into orthorhombic space group $Pmmm$ #47 and becomes antiferromagnetic. (this structure) Below 335K the iron atoms become multivalent, splitting into Fe$^{2.5\pm\delta}$ sites. This is known as a Class-II MV structure.
- Below 308K the iron atoms are fully ordered with charges Fe$^{2+}$ and Fe$^{3+}$, forming a Class-I MV structure. The space group changes to $Pmma$ #51.
- Here we use the data taken by (Woodward, 2003) at 320K.
- If we allow an uncertainty of 0.1Å in the atomic positions the space group changes to $P4/mmm$ and is nearly identical with the structure of YBaCuFeO$_{5}$ with the copper atoms removed and the iron sites fully occupied.
\[ \begin{array}{ccc}
\mathbf{a_{1}}&=&a \,\mathbf{\hat{x}}\\\mathbf{a_{2}}&=&b \,\mathbf{\hat{y}}\\\mathbf{a_{3}}&=&c \,\mathbf{\hat{z}}
\end{array}\]
Basis vectors
| Lattice coordinates | Cartesian coordinates | Wyckoff position | Atom type | |||
|---|---|---|---|---|---|---|
| $\mathbf{B_{1}}$ | = | $0$ | = | $0$ | (1a) | Ba I |
| $\mathbf{B_{2}}$ | = | $\frac{1}{2} \, \mathbf{a}_{1}$ | = | $\frac{1}{2}a \,\mathbf{\hat{x}}$ | (1b) | Y I |
| $\mathbf{B_{3}}$ | = | $\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (1g) | O I |
| $\mathbf{B_{4}}$ | = | $x_{4} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $a x_{4} \,\mathbf{\hat{x}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (2j) | O II |
| $\mathbf{B_{5}}$ | = | $- x_{4} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $- a x_{4} \,\mathbf{\hat{x}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (2j) | O II |
| $\mathbf{B_{6}}$ | = | $x_{5} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}$ | = | $a x_{5} \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}$ | (2k) | O III |
| $\mathbf{B_{7}}$ | = | $- x_{5} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}$ | = | $- a x_{5} \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}$ | (2k) | O III |
| $\mathbf{B_{8}}$ | = | $x_{6} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $a x_{6} \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (2l) | Fe I |
| $\mathbf{B_{9}}$ | = | $- x_{6} \, \mathbf{a}_{1}+\frac{1}{2} \, \mathbf{a}_{2}+\frac{1}{2} \, \mathbf{a}_{3}$ | = | $- a x_{6} \,\mathbf{\hat{x}}+\frac{1}{2}b \,\mathbf{\hat{y}}+\frac{1}{2}c \,\mathbf{\hat{z}}$ | (2l) | Fe I |
References
- P. M. Woodward and P. Karen, Mixed Valence YBaFe$_{2}$O$_{5}$, Inorg. Chem. 42, 1121–1129 (2003), doi:10.1021/ic026022z.
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=AB2C5D_oP9_47_a_l_gjk_b --params=$a,b/a,c/a,x_{4},x_{5},x_{6}$