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alpha_{H}'-Ca₂SiO₄ Ca₂O₄Si

Orthorhombic · space group Pnma (No. 62) · Pearson oP52

Symmetry elements and Wyckoff positions (interactive)

alpha_{H}'-Ca₂SiO₄ in Pnma

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

Unit cell

Lattice constants
a = 6.871 Å, b = 5.601 Å, c = 9.556 Å; α = 90.00°, β = 90.00°, γ = 90.00°
Cell volume
367.8 ų
Atoms in the conventional cell
52 (Si 4, Ca 16, O 32)
Formula units Z
4
Pearson symbol
oP52 — orthorhombic, primitive lattice, 52 atoms per conventional cell
Symmetry operations
8 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Si7Si4c40.78310.25000.5891
Ca1Ca8d80.33260.28230.5732
Ca2Ca8d80.98790.29520.2989
O3O8d80.00500.30810.5545
O4O8d80.74360.03080.7016
O5O8d80.66580.19010.4449
O6O8d80.70410.50300.6495

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 52 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

A4B8C_oP52_62_2d_4d_c-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oP52, then the space-group number 62, then the Wyckoff letters occupied by each element in turn (Si: 4c; Ca: 8d; Ca: 8d; O: 8d; O: 8d; O: 8d; O: 8d). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Sr₂SiO₄ <!--beginning with an

Note: \alpha_{H}'-Ca₂SiO₄.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A4B8C_oP52_62_2d_4d_c-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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