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Crystal Lab › Prototype structures › Monoclinic

Larnite (β-Ca₂SiO₄)

Monoclinic · space group P121/c1 (No. 14) · Pearson mP28 · mineral: larnite

Symmetry elements and Wyckoff positions (interactive)

Larnite (β-Ca₂SiO₄) in P121/c1

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

Unit cell

Lattice constants
a = 9.311 Å, b = 6.755 Å, c = 11.183 Å; α = 90.00°, β = 150.61°, γ = 90.00°
Cell volume
345.2 ų
Atoms in the conventional cell
28 (Co 8, O 16, Si 4)
Formula units Z
4
Pearson symbol
mP28 — monoclinic, primitive lattice, 28 atoms per conventional cell
Symmetry operations
4 per cell

Crystallographic sites

SiteElementWyckoffMultiplicityxyz
Co1Co4e40.92270.50240.2207
Co2Co4e40.65760.15740.2273
O3O4e40.34280.98790.2828
O4O4e40.21310.25190.0212
O5O4e40.62480.33170.4867
O6O4e40.08360.32880.1561
Si7Si4e40.31440.21870.2328

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 28 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

A2B4C_mP28_14_2e_4e_e-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mP28, then the space-group number 14, then the Wyckoff letters occupied by each element in turn (Co: 4e; Co: 4e; O: 4e; O: 4e; O: 4e; O: 4e; Si: 4e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ba₂CoO₄, β-Sr₂SiO₄ <!--beginning with an

Note: Larnite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B4C_mP28_14_2e_4e_e-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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