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NbAs

Tetragonal · space group I41md (No. 109) · Pearson tI8

Symmetry elements and Wyckoff positions (interactive)

NbAs in I41md

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

Unit cell

Lattice constants
a = 3.452 Å, b = 3.452 Å, c = 11.680 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
139.2 ų
Atoms in the conventional cell
8 (As 4, Nb 4)
Formula units Z
4
Pearson symbol
tI8 — tetragonal, body-centred lattice, 8 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
As1As4a40.00000.00000.4160
Nb2Nb4a40.00000.00000.0000

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 8 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

AB_tI8_109_a_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI8, then the space-group number 109, then the Wyckoff letters occupied by each element in turn (As: 4a; Nb: 4a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

TaAs, β-TaP, β-NbP <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB_tI8_109_a_a-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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