Crystal Lab › Prototype structures › Orthorhombic
Nd₂Si₂O₇
Orthorhombic · space group P212121 (No. 19) · Pearson oP44
Symmetry elements and Wyckoff positions (interactive)
Nd₂Si₂O₇ in P212121
SettingUnit cell
- Lattice constants
- a = 5.394 Å, b = 12.950 Å, c = 8.720 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 609.1 ų
- Atoms in the conventional cell
- 44 (Nd 8, O 28, Si 8)
- Formula units Z
- 4
- Pearson symbol
- oP44 — orthorhombic, primitive lattice, 44 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Nd1 | Nd | 4a | 4 | 0.9974 | 0.2314 | 0.4432 |
| Nd2 | Nd | 4a | 4 | 0.5072 | 0.4096 | 0.6462 |
| O3 | O | 4a | 4 | 0.4710 | 0.4340 | 0.1758 |
| O4 | O | 4a | 4 | 0.2500 | 0.2593 | 0.1696 |
| O5 | O | 4a | 4 | 0.7232 | 0.2487 | 0.2325 |
| O6 | O | 4a | 4 | 0.3947 | 0.3301 | 0.4291 |
| O7 | O | 4a | 4 | 0.2534 | 0.4205 | 0.8930 |
| O8 | O | 4a | 4 | 0.7302 | 0.4485 | 0.9074 |
| O9 | O | 4a | 4 | 0.3970 | 0.5941 | 0.9950 |
| Si10 | Si | 4a | 4 | 0.4770 | 0.3218 | 0.2494 |
| Si11 | Si | 4a | 4 | 0.4767 | 0.4748 | 0.9982 |
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 44 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_oP44_19_2a_7a_2a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP44, then the space-group number 19, then the Wyckoff letters occupied by each element in turn (Nd: 4a; Nd: 4a; O: 4a; O: 4a; O: 4a; O: 4a; O: 4a; O: 4a; O: 4a; Si: 4a; Si: 4a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ce₂Si₂O₇, Eu₂Si₂O₇, La₂Si₂O₇, Sm₂Si₂O₇ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B7C2_oP44_19_2a_7a_2a-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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