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Crystal Lab › Prototype structures › Tetragonal

α-LiNH₂ H₂LiN

Tetragonal · space group I-4 (No. 82) · Pearson tI32

Symmetry elements and Wyckoff positions (interactive)

α-LiNH₂ in I-4

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

Unit cell

Lattice constants
a = 5.034 Å, b = 5.034 Å, c = 10.256 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
259.9 ų
Atoms in the conventional cell
32 (Li 8, H 16, N 8)
Formula units Z
8
Pearson symbol
tI32 — tetragonal, body-centred lattice, 32 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Li4Li2a20.00000.00000.0000
Li3Li2c20.00000.50000.2500
Li5Li4f40.00000.50000.0025
H1H8g80.24290.12850.1910
H2H8g80.38400.35120.1278
N6N8g80.22860.24990.1158

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 32 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

A2BC_tI32_82_2g_ace_g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI32, then the space-group number 82, then the Wyckoff letters occupied by each element in turn (Li: 2a; Li: 2c; Li: 4f; H: 8g; H: 8g; N: 8g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: α/Phase I.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC_tI32_82_2g_ace_g-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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