Crystal Lab › Prototype structures › Orthorhombic
Na₂Mo₂O₇
Orthorhombic · space group Cmce (No. 64) · Pearson oC88
Symmetry elements and Wyckoff positions (interactive)
Na₂Mo₂O₇ in Cmce
SettingUnit cell
- Lattice constants
- a = 7.170 Å, b = 11.830 Å, c = 14.700 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 1246.9 ų
- Atoms in the conventional cell
- 88 (Na 16, Mo 16, O 56)
- Formula units Z
- 8
- Pearson symbol
- oC88 — orthorhombic, base-centred lattice, 88 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Na3 | Na | 8d | 8 | 0.2500 | 0.0000 | 0.0000 |
| Mo1 | Mo | 8e | 8 | 0.2500 | 0.0800 | 0.2500 |
| Mo2 | Mo | 8f | 8 | 0.0000 | 0.2500 | 0.0800 |
| Na4 | Na | 8f | 8 | 0.0000 | 0.3600 | 0.3000 |
| O5 | O | 8f | 8 | 0.0000 | 0.0800 | 0.2700 |
| O6 | O | 8f | 8 | 0.0000 | 0.4100 | 0.1300 |
| O7 | O | 8f | 8 | 0.0000 | 0.3500 | 0.4900 |
| O8 | O | 16g | 16 | 0.7100 | 0.7100 | 0.1600 |
| O9 | O | 16g | 16 | 0.7100 | 0.9900 | 0.3400 |
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 88 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
A2B2C7_oC88_64_ef_df_3f2g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC88, then the space-group number 64, then the Wyckoff letters occupied by each element in turn (Na: 8d; Mo: 8e; Mo: 8f; Na: 8f; O: 8f; O: 8f; O: 8f; O: 16g; O: 16g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Na₂W₂O₇ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C7_oC88_64_ef_df_3f2g-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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