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Crystal Lab › Prototype structures › Orthorhombic

η-Fe₂C

Orthorhombic · space group Pnnm (No. 58) · Pearson oP6

Symmetry elements and Wyckoff positions (interactive)

η-Fe₂C in Pnnm

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

Unit cell

Lattice constants
a = 4.704 Å, b = 4.318 Å, c = 2.830 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
57.5 ų
Atoms in the conventional cell
6 (C 2, Fe 4)
Formula units Z
2
Pearson symbol
oP6 — orthorhombic, primitive lattice, 6 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
C1C2a20.00000.00000.0000
Fe2Fe4g40.66670.25000.0000

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 6 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

AB2_oP6_58_a_g-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP6, then the space-group number 58, then the Wyckoff letters occupied by each element in turn (C: 2a; Fe: 4g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

C₂Si, Co₂C, Co₂N, N₂Al, N₂Os, Pd₂B, Pd₂N, Rh₂C <!--beginning with an

Note: \eta-Fe₂C.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2_oP6_58_a_g-002 (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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