Crystal Lab › Prototype structures › Orthorhombic
SrH₂ (C29)
Orthorhombic · space group Pnma (No. 62) · Pearson oP12 · Strukturbericht C29
Symmetry elements and Wyckoff positions (interactive)
SrH₂ (C29) in Pnma
SettingUnit cell
- Lattice constants
- a = 6.371 Å, b = 3.872 Å, c = 7.302 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 180.1 ų
- Atoms in the conventional cell
- 12 (H 8, Sr 4)
- Formula units Z
- 4
- Pearson symbol
- oP12 — orthorhombic, primitive lattice, 12 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| H1 | H | 4c | 4 | 0.3570 | 0.2500 | 0.4281 |
| H2 | H | 4c | 4 | 0.9693 | 0.2500 | 0.6825 |
| Sr3 | Sr | 4c | 4 | 0.2438 | 0.2500 | 0.1108 |
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 12 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
A2B_oP12_62_2c_c-004: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP12, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (H: 4c; H: 4c; Sr: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
CaH₂, EuD₂, YbH₂ <!--beginning with an
Note: C29.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B_oP12_62_2c_c-004 (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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