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Archerite (KH₂PO₄)

Orthorhombic · space group Fdd2 (No. 43) · Pearson oF64 · mineral: archerite

Symmetry elements and Wyckoff positions (interactive)

Archerite (KH₂PO₄) in Fdd2

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

Unit cell

Lattice constants
a = 10.530 Å, b = 10.440 Å, c = 6.900 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
758.5 ų
Atoms in the conventional cell
64 (K 8, P 8, H 16, O 32)
Formula units Z
8
Pearson symbol
oF64 — orthorhombic, face-centred lattice, 64 atoms per conventional cell
Symmetry operations
16 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
K2K8a80.00000.00000.4880
P5P8a80.00000.00000.0000
H1H16b160.06200.71250.6145
O3O16b160.13400.78450.6190
O4O16b160.28450.86600.8735

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 64 atoms drawn above are these sites multiplied by all 16 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

A2BC4D_oF64_43_b_a_2b_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oF64, then the space-group number 43, then the Wyckoff letters occupied by each element in turn (K: 8a; P: 8a; H: 16b; O: 16b; O: 16b). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Archerite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2BC4D_oF64_43_b_a_2b_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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