Crystal Lab › Prototype structures › Trigonal
Calcite (CaCO₃, G0₁)
Trigonal · space group R-3c (No. 167) · Pearson hR10 · Strukturbericht G01 · mineral: calcite
Symmetry elements and Wyckoff positions (interactive)
Calcite (CaCO₃, G0₁) in R-3c
SettingUnit cell
- Lattice constants
- a = 4.988 Å, b = 4.988 Å, c = 17.061 Å; α = 90.00°, β = 90.00°, γ = 120.00°
- Cell volume
- 367.6 ų
- Atoms in the conventional cell
- 30 (C 6, Ca 6, O 18)
- Formula units Z
- 6
- Pearson symbol
- hR10 — hexagonal / trigonal, rhombohedral lattice, 10 atoms per conventional cell
- Symmetry operations
- 36 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| C1 | C | 6a | 6 | 0.0000 | 0.0000 | 0.2500 |
| Ca2 | Ca | 6b | 6 | 0.0000 | 0.0000 | 0.0000 |
| O3 | O | 18e | 18 | 0.2567 | 0.0000 | 0.2500 |
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 30 atoms drawn above are these sites multiplied by all 36 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
ABC3_hR10_167_a_b_e-002: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hR10, then the space-group number 167, then the Wyckoff letters occupied by each element in turn (C: 6a; Ca: 6b; O: 18e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Other compounds with this structure
AlBO₃, (Ca, Mn)CO₃ (kutnohorite, rhodocrosite), CdCO₃ (otavite), (Cd, Mg)CO₃ (otavite), CoCO₃ (spherocobaltite), CuCO₃, FeCO₃ (siderite), InBO₃, (La, Na)O₃ (loparite), LaNiO₃, MgCO₃ (magnesite), MnCO₃ (rhodochrosite), NaNO₃ (nitratine), NiCO₃ (gaspeite), ZnCO₃ (smithsonite) <!--beginning with an
Note: G0₁, Calcite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry ABC3_hR10_167_a_b_e-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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