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
SettingUnit 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
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Co1 | Co | 4e | 4 | 0.9227 | 0.5024 | 0.2207 |
| Co2 | Co | 4e | 4 | 0.6576 | 0.1574 | 0.2273 |
| O3 | O | 4e | 4 | 0.3428 | 0.9879 | 0.2828 |
| O4 | O | 4e | 4 | 0.2131 | 0.2519 | 0.0212 |
| O5 | O | 4e | 4 | 0.6248 | 0.3317 | 0.4867 |
| O6 | O | 4e | 4 | 0.0836 | 0.3288 | 0.1561 |
| Si7 | Si | 4e | 4 | 0.3144 | 0.2187 | 0.2328 |
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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