Crystal Lab › Prototype structures › Orthorhombic
HgCl₂ (C25)
Orthorhombic · space group Pnma (No. 62) · Pearson oP12 · Strukturbericht C25
Symmetry elements and Wyckoff positions (interactive)
HgCl₂ (C25) in Pnma
SettingUnit cell
- Lattice constants
- a = 12.735 Å, b = 5.963 Å, c = 4.325 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 328.4 ų
- Atoms in the conventional cell
- 12 (Cl 8, Hg 4)
- Formula units Z
- 4
- Pearson symbol
- oP12 — orthorhombic, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cl1 | Cl | 4c | 4 | 0.7330 | 0.2500 | 0.1250 |
| Cl2 | Cl | 4c | 4 | 0.5080 | 0.2500 | 0.7220 |
| Hg3 | Hg | 4c | 4 | 0.8740 | 0.2500 | 0.4470 |
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 12 atoms drawn above are these sites multiplied by all 8 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
A2B_oP12_62_2c_c-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP12, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (Cl: 4c; Cl: 4c; Hg: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
FeO₂ (goethite) <!--beginning with an
Note: C25.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oP12_62_2c_c-002 (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.
← Co₂Si (C37) · Space group Pnma (113 prototypes) · All prototypes · Cotunnite (PbCl₂, C23) →