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Crystal Lab › Prototype structures › Hexagonal

Al₇C₃N₃

Hexagonal · space group P63mc (No. 186) · Pearson hP26

Symmetry elements and Wyckoff positions (interactive)

Al₇C₃N₃ in P63mc

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

Unit cell

Lattice constants
a = 3.227 Å, b = 3.227 Å, c = 31.700 Å; α = 90.00°, β = 90.00°, γ = 120.00°
Cell volume
285.8 ų
Atoms in the conventional cell
26 (Al 14, C 6, Ni 6)
Formula units Z
2
Pearson symbol
hP26 — hexagonal / trigonal, primitive lattice, 26 atoms per conventional cell
Symmetry operations
12 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Al1Al2a20.00000.00000.1085
Al2Al2a20.00000.00000.2615
Al3Al2a20.00000.00000.3915
C8C2a20.00000.00000.0009
C9C2a20.00000.00000.3267
Ni11Ni2a20.00000.00000.1686
Al4Al2b20.33330.66670.5299
Al5Al2b20.33330.66670.6844
Al6Al2b20.33330.66670.8166
Al7Al2b20.33330.66670.9659
C10C2b20.33330.66670.7448
Ni12Ni2b20.33330.66670.5939
Ni13Ni2b20.33330.66670.9069

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 12 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

A7B3C3_hP26_186_3a4b_2ab_a2b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP26, then the space-group number 186, then the Wyckoff letters occupied by each element in turn (Al: 2a; Al: 2a; Al: 2a; C: 2a; C: 2a; Ni: 2a; Al: 2b; Al: 2b; Al: 2b; Al: 2b; C: 2b; Ni: 2b; Ni: 2b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

(Al_{7-x}Si_{x})(O_{y}C_{z}N_{6-y-z}) <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A7B3C3_hP26_186_3a4b_2ab_a2b-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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