Crystal Lab › Prototype structures › Orthorhombic
Clinobarylite (BaBe₂Si₂O₇)
Orthorhombic · space group Pmn21 (No. 31) · Pearson oP24 · mineral: clinobarylite
Symmetry elements and Wyckoff positions (interactive)
Clinobarylite (BaBe₂Si₂O₇) in Pmn21
SettingUnit cell
- Lattice constants
- a = 11.649 Å, b = 4.918 Å, c = 4.675 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 267.8 ų
- Atoms in the conventional cell
- 24 (Ba 2, O 14, Be 4, Si 4)
- Formula units Z
- 2
- Pearson symbol
- oP24 — orthorhombic, primitive lattice, 24 atoms per conventional cell
- Symmetry operations
- 4 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ba1 | Ba | 2a | 2 | 0.0000 | 0.7968 | 0.0905 |
| O3 | O | 2a | 2 | 0.0000 | 0.2236 | 0.6793 |
| Be2 | Be | 4b | 4 | 0.7511 | 0.1693 | 0.0849 |
| O4 | O | 4b | 4 | 0.6390 | 0.3560 | 0.1367 |
| O5 | O | 4b | 4 | 0.7769 | 0.1340 | 0.7298 |
| O6 | O | 4b | 4 | 0.6327 | 0.7295 | 0.7284 |
| Si7 | Si | 4b | 4 | 0.6283 | 0.6753 | 0.0692 |
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 24 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
AB2C7D2_oP24_31_a_b_a3b_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP24, then the space-group number 31, then the Wyckoff letters occupied by each element in turn (Ba: 2a; O: 2a; Be: 4b; O: 4b; O: 4b; O: 4b; Si: 4b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Clinobarylite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C7D2_oP24_31_a_b_a3b_b-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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