Crystal Lab › Prototype structures › Monoclinic
Predicted SiO₂ (P2)
Monoclinic · space group P121 (No. 3) · Pearson mP12
Symmetry elements and Wyckoff positions (interactive)
Predicted SiO₂ (P2) in P121
SettingUnit cell
- Lattice constants
- a = 7.421 Å, b = 4.129 Å, c = 7.759 Å; α = 90.00°, β = 148.29°, γ = 90.00°
- Cell volume
- 125.0 ų
- Atoms in the conventional cell
- 12 (O 8, Si 4)
- Formula units Z
- 4
- Pearson symbol
- mP12 — monoclinic, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 2 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| O1 | O | 1b | 1 | 0.0000 | 0.1591 | 0.5000 |
| O2 | O | 1a | 1 | 0.0000 | 0.7386 | 0.0000 |
| O3 | O | 2e | 2 | 0.3347 | 0.7520 | 0.5240 |
| O4 | O | 2e | 2 | 0.2449 | 0.7147 | 0.8856 |
| O5 | O | 2e | 2 | 0.8016 | 0.2020 | 0.9896 |
| Si6 | Si | 2e | 2 | 0.9859 | 0.0000 | 0.6824 |
| Si7 | Si | 2e | 2 | 0.7030 | 0.5856 | 0.8810 |
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 12 atoms drawn above are these sites multiplied by all 2 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
A2B_mP12_3_ab3e_2e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP12, then the space-group number 3, then the Wyckoff letters occupied by each element in turn (O: 1b; O: 1a; O: 2e; O: 2e; O: 2e; Si: 2e; Si: 2e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Predicted.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_mP12_3_ab3e_2e-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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