Crystal Lab › Prototype structures › Orthorhombic
NH₄HF₂ (F5₈)
Orthorhombic · space group Pmna (No. 53) · Pearson oP16 · Strukturbericht F58
Symmetry elements and Wyckoff positions (interactive)
NH₄HF₂ (F5₈) in Pmna
SettingUnit cell
- Lattice constants
- a = 8.426 Å, b = 3.690 Å, c = 8.180 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 254.3 ų
- Atoms in the conventional cell
- 16 (H 4, F 8, N 4)
- Formula units Z
- 4
- Pearson symbol
- oP16 — orthorhombic, primitive lattice, 16 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| H4 | H | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| H3 | H | 2b | 2 | 0.5000 | 0.0000 | 0.0000 |
| F1 | F | 4e | 4 | 0.1370 | 0.0000 | 0.0000 |
| NH5 | N | 4g | 4 | 0.2500 | 0.4600 | 0.2500 |
| F2 | F | 4h | 4 | 0.0000 | 0.1310 | 0.6290 |
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 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_oP16_53_eh_ab_g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP16, then the space-group number 53, then the Wyckoff letters occupied by each element in turn (H: 2a; H: 2b; F: 4e; N: 4g; F: 4h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: F5₈.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC_oP16_53_eh_ab_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.
← Eriochalcite (CuCl₂cdot2H₂O, C45) · Space group Pmna (4 prototypes) · All prototypes · TaNiTe₂ →