Crystal Lab › Prototype structures › Tetragonal
BaTi₂As₂O
Tetragonal · space group P4/mmm (No. 123) · Pearson tP6
Symmetry elements and Wyckoff positions (interactive)
BaTi₂As₂O in P4/mmm
SettingUnit cell
- Lattice constants
- a = 4.047 Å, b = 4.047 Å, c = 7.275 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 119.2 ų
- Atoms in the conventional cell
- 6 (Ba 1, O 1, Ti 2, As 2)
- Formula units Z
- 1
- Pearson symbol
- tP6 — tetragonal, primitive lattice, 6 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Ba1 | Ba | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| O2 | O | 1b | 1 | 0.0000 | 0.0000 | 0.5000 |
| Ti3 | Ti | 2e | 2 | 0.0000 | 0.5000 | 0.5000 |
| As4 | As | 2h | 2 | 0.5000 | 0.5000 | 0.2560 |
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 6 atoms drawn above are these sites multiplied by all 16 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
A2BCD2_tP6_123_h_a_b_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP6, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (Ba: 1a; O: 1b; Ti: 2e; As: 2h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
BaBi₂Ti₂O, BaTi₂Sb₂O <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BCD2_tP6_123_h_a_b_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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