Crystal Lab › Prototype structures › Hexagonal
LaTa₇O₁₉
Hexagonal · space group P-6c2 (No. 188) · Pearson hP54
Symmetry elements and Wyckoff positions (interactive)
LaTa₇O₁₉ in P-6c2
SettingUnit cell
- Lattice constants
- a = 6.230 Å, b = 6.230 Å, c = 19.990 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 671.9 ų
- Atoms in the conventional cell
- 54 (La 2, Ta 14, O 38)
- Formula units Z
- 2
- Pearson symbol
- hP54 — hexagonal / trigonal, primitive lattice, 54 atoms per conventional cell
- Symmetry operations
- 12 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| La1 | La | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Ta2 | Ta | 2c | 2 | 0.3333 | 0.6667 | 0.0000 |
| O3 | O | 4g | 4 | 0.0000 | 0.0000 | 0.1270 |
| O4 | O | 4h | 4 | 0.3333 | 0.6667 | 0.1640 |
| O5 | O | 6k | 6 | 0.7077 | 0.7443 | 0.2500 |
| O6 | O | 12l | 12 | 0.6567 | 0.0833 | 0.1560 |
| O7 | O | 12l | 12 | 0.6107 | 0.7003 | 0.0610 |
| Ta8 | Ta | 12l | 12 | 0.6647 | 0.6923 | 0.1563 |
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 54 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
AB19C7_hP54_188_a_ghk2l_cl-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP54, then the space-group number 188, then the Wyckoff letters occupied by each element in turn (La: 2a; Ta: 2c; O: 4g; O: 4h; O: 6k; O: 12l; O: 12l; Ta: 12l). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
BiTa₇O₁₉, DyTa₇O₁₉, GdTa₇O₁₉, HoTa₇O₁₉, NdTa₇O₁₉, PrTa₇O₁₉, SmTa₇O₁₉ <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB19C7_hP54_188_a_ghk2l_cl-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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