Crystal Lab › Prototype structures › Tetragonal
α-LiNH₂ H₂LiN
Tetragonal · space group I-4 (No. 82) · Pearson tI32
Symmetry elements and Wyckoff positions (interactive)
α-LiNH₂ in I-4
SettingUnit cell
- Lattice constants
- a = 5.034 Å, b = 5.034 Å, c = 10.256 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 259.9 ų
- Atoms in the conventional cell
- 32 (Li 8, H 16, N 8)
- Formula units Z
- 8
- Pearson symbol
- tI32 — tetragonal, body-centred lattice, 32 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Li4 | Li | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Li3 | Li | 2c | 2 | 0.0000 | 0.5000 | 0.2500 |
| Li5 | Li | 4f | 4 | 0.0000 | 0.5000 | 0.0025 |
| H1 | H | 8g | 8 | 0.2429 | 0.1285 | 0.1910 |
| H2 | H | 8g | 8 | 0.3840 | 0.3512 | 0.1278 |
| N6 | N | 8g | 8 | 0.2286 | 0.2499 | 0.1158 |
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 32 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
A2BC_tI32_82_2g_ace_g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI32, then the space-group number 82, then the Wyckoff letters occupied by each element in turn (Li: 2a; Li: 2c; Li: 4f; H: 8g; H: 8g; N: 8g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: α/Phase I.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC_tI32_82_2g_ace_g-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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