Crystal Lab › Prototype structures › Trigonal
Ba₃SrTa₂O₉
Trigonal · space group P-3m1 (No. 164) · Pearson hP15
Symmetry elements and Wyckoff positions (interactive)
Ba₃SrTa₂O₉ in P-3m1
SettingUnit cell
- Lattice constants
- a = 5.950 Å, b = 5.950 Å, c = 7.470 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 229.0 ų
- Atoms in the conventional cell
- 15 (Ba 3, Sr 1, Ta 2, O 9)
- Formula units Z
- 1
- Pearson symbol
- hP15 — hexagonal / trigonal, primitive lattice, 15 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ba1 | Ba | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| Sr5 | Sr | 1b | 1 | 0.0000 | 0.0000 | 0.5000 |
| Ba2 | Ba | 2d | 2 | 0.3333 | 0.6667 | 0.6667 |
| Ta6 | Ta | 2d | 2 | 0.3333 | 0.6667 | 0.1667 |
| O3 | O | 3e | 3 | 0.5000 | 0.0000 | 0.0000 |
| O4 | O | 6i | 6 | 0.1667 | 0.8333 | 0.3333 |
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 15 atoms drawn above are these sites multiplied by all 12 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
A3B9CD2_hP15_164_ad_ei_b_d-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP15, then the space-group number 164, then the Wyckoff letters occupied by each element in turn (Ba: 1a; Sr: 1b; Ba: 2d; Ta: 2d; O: 3e; O: 6i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Ba₃CoNb₂O₉ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A3B9CD2_hP15_164_ad_ei_b_d-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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