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Crystal Lab › Prototype structures › Orthorhombic

NaCu₂O₂

Orthorhombic · space group Pnma (No. 62) · Pearson oP20

Symmetry elements and Wyckoff positions (interactive)

NaCu₂O₂ in Pnma

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

Unit cell

Lattice constants
a = 6.200 Å, b = 2.931 Å, c = 13.034 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
236.9 ų
Atoms in the conventional cell
20 (Cu 8, Na 4, O 8)
Formula units Z
4
Pearson symbol
oP20 — orthorhombic, primitive lattice, 20 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Cu1Cu4c40.38100.25000.2549
Cu2Cu4c40.86940.25000.6059
Na3Na4c40.35800.25000.5806
O4O4c40.41890.25000.1155
O5O4c40.34890.25000.3979

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 20 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

A2BC2_oP20_62_2c_c_2c-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP20, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (Cu: 4c; Cu: 4c; Na: 4c; O: 4c; O: 4c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

LiCu₂O₂ <!--beginning with an

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC2_oP20_62_2c_c_2c-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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