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Crystal Lab › Prototype structures › Orthorhombic

K₂CdPb

Orthorhombic · space group Ama2 (No. 40) · Pearson oC16

Symmetry elements and Wyckoff positions (interactive)

K₂CdPb in Ama2

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

Unit cell

Lattice constants
a = 6.458 Å, b = 8.602 Å, c = 10.955 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
608.6 ų
Atoms in the conventional cell
16 (Cd 4, K 8, Pb 4)
Formula units Z
4
Pearson symbol
oC16 — orthorhombic, base-centred lattice, 16 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cd1Cd4a40.00000.00000.0000
K2K4b40.25000.34670.1773
K3K4b40.25000.36610.8301
Pb4Pb4b40.25000.72810.0093

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 16 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

AB2C_oC16_40_a_2b_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC16, then the space-group number 40, then the Wyckoff letters occupied by each element in turn (Cd: 4a; K: 4b; K: 4b; Pb: 4b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

K₂CdSn <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C_oC16_40_a_2b_b-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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