Crystal Lab › Prototype structures › Orthorhombic
Mg(NH₃)₂Cl₂ (E1₃)
Orthorhombic · space group Cmmm (No. 65) · Pearson oC26 · Strukturbericht E13
Symmetry elements and Wyckoff positions (interactive)
Mg(NH₃)₂Cl₂ (E1₃) in Cmmm
SettingUnit cell
- Lattice constants
- a = 8.181 Å, b = 8.207 Å, c = 3.755 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 252.1 ų
- Atoms in the conventional cell
- 26 (Mg 2, Cl 4, N 4, H 16)
- Formula units Z
- 2
- Pearson symbol
- oC26 — orthorhombic, base-centred lattice, 26 atoms per conventional cell
- Symmetry operations
- 16 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Mg3 | Mg | 2a | 2 | 0.0000 | 0.0000 | 0.0000 |
| Cl1 | Cl | 4h | 4 | 0.2133 | 0.0000 | 0.5000 |
| N4 | N | 4i | 4 | 0.0000 | 0.2595 | 0.0000 |
| H2 | H | 16r | 16 | 0.5450 | 0.8120 | 0.1580 |
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 26 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
A2B8CD2_oC26_65_h_r_a_i-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC26, then the space-group number 65, then the Wyckoff letters occupied by each element in turn (Mg: 2a; Cl: 4h; N: 4i; H: 16r). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
Cd(NH₃)₂Cl₂, Mg(NH₃)₂Cl₂, Hg(NH₃)₂Cl₂, Ni(NH₃)₂Br₂, Ni(NH₃)₂Cl₂, Ni(NH₃)₂I₂ <!--beginning with an
Note: E1₃.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B8CD2_oC26_65_h_r_a_i-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.
← Li₇Ge₂ · Space group Cmmm (19 prototypes) · All prototypes · Ga₂Zr →