Paralstonite (BaCa(CO₃)₂)

Unit cell

Lattice constants

a = 8.692 Å, b = 8.692 Å, c = 6.148 Å; α = 90.00°, β = 90.00°, γ = 120.00°

Cell volume

402.3 ų

Atoms in the conventional cell

30 (C 6, Ba 3, Ca 3, O 18)

Formula units Z

3

Pearson symbol

hP30 — hexagonal / trigonal, primitive lattice, 30 atoms per conventional cell

Symmetry operations

6 per cell

Crystallographic sites

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 6 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

AB2CD6_hP30_150_e_c2d_f_3g-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP30, then the space-group number 150, then the Wyckoff letters occupied by each element in turn (C: 2c; C: 2d; C: 2d; Ba: 3e; Ca: 3f; O: 6g; O: 6g; O: 6g). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Paralstonite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2CD6_hP30_150_e_c2d_f_3g-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.