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Crystal Lab › Prototype structures › Monoclinic

K₂Ni(CN)₄

Monoclinic · space group P121/c1 (No. 14) · Pearson mP22

Symmetry elements and Wyckoff positions (interactive)

K₂Ni(CN)₄ in P121/c1

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

Unit cell

Lattice constants
a = 4.294 Å, b = 7.680 Å, c = 13.030 Å; α = 90.00°, β = 87.27°, γ = 90.00°
Cell volume
429.2 ų
Atoms in the conventional cell
22 (Ni 2, C 8, K 4, N 8)
Formula units Z
2
Pearson symbol
mP22 — monoclinic, primitive lattice, 22 atoms per conventional cell
Symmetry operations
4 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Ni6Ni2a20.00000.00000.0000
C1C4e40.83300.20700.9450
C2C4e40.15100.38200.6100
K3K4e40.71900.04600.6590
N4N4e40.73900.33800.9180
N5N4e40.23600.30000.6730

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 22 atoms drawn above are these sites multiplied by all 4 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

A4B2C4D_mP22_14_2e_e_2e_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP22, then the space-group number 14, then the Wyckoff letters occupied by each element in turn (Ni: 2a; C: 4e; C: 4e; K: 4e; N: 4e; N: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A4B2C4D_mP22_14_2e_e_2e_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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