Crystal Lab › Prototype structures › Orthorhombic
NH₄NO₃ III (G0₁₀)
Orthorhombic · space group Pnma (No. 62) · Pearson oP20 · Strukturbericht G010
Symmetry elements and Wyckoff positions (interactive)
NH₄NO₃ III (G0₁₀) in Pnma
SettingUnit cell
- Lattice constants
- a = 7.650 Å, b = 5.830 Å, c = 7.140 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 318.4 ų
- Atoms in the conventional cell
- 20 (N 8, O 12)
- Formula units Z
- 4
- Pearson symbol
- oP20 — orthorhombic, primitive lattice, 20 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| N1 | N | 4c | 4 | 0.1450 | 0.2500 | 0.1400 |
| NH2 | N | 4c | 4 | 0.0200 | 0.2500 | 0.6800 |
| O3 | O | 4c | 4 | 0.0850 | 0.2500 | 0.3000 |
| O4 | O | 8d | 8 | 0.1750 | 0.0600 | 0.0600 |
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 20 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
ABC3_oP20_62_c_c_cd-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP20, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (N: 4c; N: 4c; O: 4c; O: 8d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: G0₁₀, NH₄NO₃ III.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC3_oP20_62_c_c_cd-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.
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