Crystal Lab › Prototype structures › Monoclinic
Er₂Si₂O₇
Monoclinic · space group P121/c1 (No. 14) · Pearson mP22
Symmetry elements and Wyckoff positions (interactive)
Er₂Si₂O₇ in P121/c1
SettingUnit cell
- Lattice constants
- a = 4.683 Å, b = 10.790 Å, c = 5.556 Å; α = 90.00°, β = 96.00°, γ = 90.00°
- Cell volume
- 279.2 ų
- Atoms in the conventional cell
- 22 (O 14, Er 4, Si 4)
- Formula units Z
- 2
- Pearson symbol
- mP22 — monoclinic, primitive lattice, 22 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| O2 | O | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Er1 | Er | 4e | 4 | 0.3883 | 0.1507 | 0.5932 |
| O3 | O | 4e | 4 | 0.7052 | 0.0514 | 0.3653 |
| O4 | O | 4e | 4 | 0.6235 | 0.1809 | 0.9583 |
| O5 | O | 4e | 4 | 0.1184 | 0.2016 | 0.2522 |
| Si6 | Si | 4e | 4 | 0.8601 | 0.1129 | 0.1442 |
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 22 atoms drawn above are these sites multiplied by all 4 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
A2B7C2_mP22_14_e_a3e_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP22, then the space-group number 14, then the Wyckoff letters occupied by each element in turn (O: 2a; Er: 4e; O: 4e; O: 4e; O: 4e; Si: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ho₂Si₂O₇, Y₂Si₂O₇ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B7C2_mP22_14_e_a3e_e-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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