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γ-Alane (AlH₃)

Orthorhombic · space group Pnnm (No. 58) · Pearson oP24 · mineral: gamma-alane

Symmetry elements and Wyckoff positions (interactive)

γ-Alane (AlH₃) in Pnnm

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

Unit cell

Lattice constants
a = 5.381 Å, b = 7.356 Å, c = 5.775 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
228.6 ų
Atoms in the conventional cell
24 (Al 6, H 18)
Formula units Z
6
Pearson symbol
oP24 — orthorhombic, primitive lattice, 24 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al2a20.00000.00000.0000
H3H2c20.00000.50000.0000
Al2Al4g40.71250.58490.0000
H4H4g40.87400.77800.0000
H5H4g40.40600.63000.0000
H6H8h80.73800.57800.6910

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 24 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

AB3_oP24_58_ag_c2gh-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP24, then the space-group number 58, then the Wyckoff letters occupied by each element in turn (Al: 2a; H: 2c; Al: 4g; H: 4g; H: 4g; H: 8h). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: \gamma-Alane.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB3_oP24_58_ag_c2gh-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.

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