Crystal Lab › Prototype structures › Tetragonal
Mercury Cyanide [Hg(CN)₂, F1₁]
Tetragonal · space group I-42d (No. 122) · Pearson tI40 · Strukturbericht F11 · mineral: mercury cyanide
Symmetry elements and Wyckoff positions (interactive)
Mercury Cyanide [Hg(CN)₂, F1₁] in I-42d
SettingUnit cell
- Lattice constants
- a = 9.692 Å, b = 9.692 Å, c = 8.902 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 836.2 ų
- Atoms in the conventional cell
- 40 (Hg 8, C 16, N 16)
- Formula units Z
- 8
- Pearson symbol
- tI40 — tetragonal, body-centred lattice, 40 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Hg2 | Hg | 8d | 8 | 0.2120 | 0.2500 | 0.1250 |
| C1 | C | 16e | 16 | 0.7035 | 0.4271 | 0.6785 |
| N3 | N | 16e | 16 | 0.7050 | 0.5464 | 0.6639 |
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 40 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
A2BC2_tI40_122_e_d_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI40, then the space-group number 122, then the Wyckoff letters occupied by each element in turn (Hg: 8d; C: 16e; N: 16e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: F1₁, Mercury Cyanide.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2_tI40_122_e_d_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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