Crystal Lab › Prototype structures › Tetragonal
HgBa₂CaCu₂O_{6+delta} Ba₂CaCu₂HgO₇
Tetragonal · space group P4/mmm (No. 123) · Pearson tP13
Symmetry elements and Wyckoff positions (interactive)
HgBa₂CaCu₂O_{6+delta} in P4/mmm
SettingUnit cell
- Lattice constants
- a = 3.853 Å, b = 3.853 Å, c = 12.652 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 187.8 ų
- Atoms in the conventional cell
- 13 (O 7, Ca 1, Hg 1, Ba 2, Cu 2)
- Formula units Z
- 1
- Pearson symbol
- tP13 — tetragonal, primitive lattice, 13 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| O5 | O | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| Ca2 | Ca | 1b | 1 | 0.0000 | 0.0000 | 0.5000 |
| Hg4 | Hg | 1c | 1 | 0.5000 | 0.5000 | 0.0000 |
| Ba1 | Ba | 2g | 2 | 0.0000 | 0.0000 | 0.2216 |
| Cu3 | Cu | 2h | 2 | 0.5000 | 0.5000 | 0.3771 |
| O6 | O | 2h | 2 | 0.5000 | 0.5000 | 0.1565 |
| O7 | O | 4i | 4 | 0.0000 | 0.5000 | 0.3772 |
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 13 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
A2BC2DE7_tP13_123_g_b_h_c_ahi-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP13, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (O: 1a; Ca: 1b; Hg: 1c; Ba: 2g; Cu: 2h; O: 2h; O: 4i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
TlBa₂CaCu₂O_{6+delta} <!--beginning with an
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2DE7_tP13_123_g_b_h_c_ahi-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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