Skip to content

Crystal Lab › Prototype structures › Orthorhombic

NH₄NO₃ IV (G0₁₁)

Orthorhombic · space group Pmmn (No. 59) · Pearson oP18 · Strukturbericht G011

Symmetry elements and Wyckoff positions (interactive)

NH₄NO₃ IV (G0₁₁) in Pmmn

Setting
Loading the group…
x = 0.10, y = 0.17, z = 0.08

Unit cell

Lattice constants
a = 5.438 Å, b = 5.745 Å, c = 4.942 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
154.4 ų
Atoms in the conventional cell
18 (N 4, O 6, H 8)
Formula units Z
2
Pearson symbol
oP18 — orthorhombic, primitive lattice, 18 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
N3N2a20.25000.25000.4933
O5O2a20.25000.25000.2371
N4N2b20.25000.75000.0836
H2H4e40.25000.89550.1898
O6O4e40.25000.06560.6168
H1H4f40.89890.25000.0324

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 18 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

A4B2C3_oP18_59_ef_ab_ae-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP18, then the space-group number 59, then the Wyckoff letters occupied by each element in turn (N: 2a; O: 2a; N: 2b; H: 4e; O: 4e; H: 4f). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: G0₁₁, NH₄NO₃ IV.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A4B2C3_oP18_59_ef_ab_ae-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.

← β-TiCu₃ (D0_{a})  ·  Space group Pmmn (11 prototypes)  ·  All prototypes  ·  Shcherbinaite (V₂O₅) Structure ( Revised ): A5B2_oP14_59_a2e_e-001 →