Crystal Lab › Prototype structures › Orthorhombic
NaNbO₃ Cmcm Lueshite Perovskite
Orthorhombic · space group Cmcm (No. 63) · Pearson oC40
Symmetry elements and Wyckoff positions (interactive)
NaNbO₃ Cmcm Lueshite Perovskite in Cmcm
SettingUnit cell
- Lattice constants
- a = 7.868 Å, b = 7.862 Å, c = 7.871 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 486.9 ų
- Atoms in the conventional cell
- 40 (Na 8, Nb 8, O 24)
- Formula units Z
- 8
- Pearson symbol
- oC40 — orthorhombic, base-centred lattice, 40 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Na1 | Na | 4c | 4 | 0.0000 | 0.0105 | 0.2500 |
| Na2 | Na | 4c | 4 | 0.0000 | 0.4836 | 0.2500 |
| Nb3 | Nb | 8d | 8 | 0.2500 | 0.2500 | 0.0000 |
| O4 | O | 8e | 8 | 0.2809 | 0.0000 | 0.0000 |
| O5 | O | 8f | 8 | 0.0000 | 0.2338 | 0.0092 |
| O6 | O | 8g | 8 | 0.7771 | 0.7579 | 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 40 atoms drawn above are these sites multiplied by all 16 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
ABC3_oC40_63_2c_d_efg-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC40, then the space-group number 63, then the Wyckoff letters occupied by each element in turn (Na: 4c; Na: 4c; Nb: 8d; O: 8e; O: 8f; O: 8g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AgNbO₃, AgTaO₃, BrSAg₃, NaTaO₃, SrHfO₃, SrZrO₃ <!--beginning with an
Note: Cmcm-Lueshite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC3_oC40_63_2c_d_efg-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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