Crystal Lab › Prototype structures › Orthorhombic
Orthorhombic Bi₃NbTiO₉ m = 2 Aurivillius Bi₃Nb₂O₉
Orthorhombic · space group Fmmm (No. 69) · Pearson oF56
Symmetry elements and Wyckoff positions (interactive)
Orthorhombic Bi₃NbTiO₉ m = 2 Aurivillius in Fmmm
SettingUnit cell
- Lattice constants
- a = 25.110 Å, b = 5.405 Å, c = 5.442 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 738.6 ų
- Atoms in the conventional cell
- 56 (Bi 12, O 36, Nb 8)
- Formula units Z
- 4
- Pearson symbol
- oF56 — orthorhombic, face-centred lattice, 56 atoms per conventional cell
- Symmetry operations
- 32 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Bi1 | Bi | 4a | 4 | 0.0000 | 0.0000 | 0.0000 |
| O4 | O | 4b | 4 | 0.0000 | 0.0000 | 0.5000 |
| O5 | O | 8f | 8 | 0.2500 | 0.2500 | 0.2500 |
| Bi2 | Bi | 8g | 8 | 0.2000 | 0.0000 | 0.0000 |
| Nb3 | Nb | 8g | 8 | 0.4120 | 0.0000 | 0.0000 |
| O6 | O | 8g | 8 | 0.3240 | 0.0000 | 0.0000 |
| O7 | O | 16l | 16 | 0.5880 | 0.2500 | 0.2500 |
The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 56 atoms drawn above are these sites multiplied by all 32 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.
How to read the label
A3B2C9_oF56_69_ag_g_bfgl-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF56, then the space-group number 69, then the Wyckoff letters occupied by each element in turn (Bi: 4a; O: 4b; O: 8f; Bi: 8g; Nb: 8g; O: 8g; O: 16l). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
BaBi₂Nb₂O₉, CaBi₂Nb₂O₉, KBi₂Nb₂O₉, NaBi₂Nb₂O₉, PbBi₂Nb₂O₉, SrBi₂Nb₂O₉ <!--beginning with an
Note: m = 2 Aurivillius.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B2C9_oF56_69_ag_g_bfgl-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.
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