Crystal Lab › Prototype structures › Tetragonal
HgBa₂Ca₂Cu₃O₈ (Hg-1223)
Tetragonal · space group P4/mmm (No. 123) · Pearson tP16
Symmetry elements and Wyckoff positions (interactive)
HgBa₂Ca₂Cu₃O₈ (Hg-1223) in P4/mmm
SettingUnit cell
- Lattice constants
- a = 3.846 Å, b = 3.846 Å, c = 15.773 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 233.3 ų
- Atoms in the conventional cell
- 16 (Hg 1, Cu 3, O 8, Ba 2, Ca 2)
- Formula units Z
- 1
- Pearson symbol
- tP16 — tetragonal, primitive lattice, 16 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Hg1 | Hg | 1a | 1 | 0.0000 | 0.0000 | 0.0000 |
| Cu2 | Cu | 1b | 1 | 0.0000 | 0.0000 | 0.5000 |
| O3 | O | 2e | 2 | 0.0000 | 0.5000 | 0.5000 |
| Cu4 | Cu | 2g | 2 | 0.0000 | 0.0000 | 0.2988 |
| O5 | O | 2g | 2 | 0.0000 | 0.0000 | 0.1246 |
| Ba6 | Ba | 2h | 2 | 0.5000 | 0.5000 | 0.1735 |
| Ca7 | Ca | 2h | 2 | 0.5000 | 0.5000 | 0.3973 |
| O8 | O | 4i | 4 | 0.0000 | 0.5000 | 0.3009 |
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 16 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
A2B2C3DE8_tP16_123_h_h_bg_a_egi-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tP16, then the space-group number 123, then the Wyckoff letters occupied by each element in turn (Hg: 1a; Cu: 1b; O: 2e; Cu: 2g; O: 2g; Ba: 2h; Ca: 2h; O: 4i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Hg-1223.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C3DE8_tP16_123_h_h_bg_a_egi-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.
· Space group P4/mmm (31 prototypes) · All prototypes · Tetragonal Ba₂YCu_{3-x}O_{7-y} — Ba₂Cu₃O₇Y →