Hexagonal high-temperature tridymite AlPO₄: AB4C_hP12_186_b_bc_b-001 AlO₄P

Unit cell

Lattice constants

a = 5.098 Å, b = 5.098 Å, c = 8.344 Å; α = 90.00°, β = 90.00°, γ = 120.00°

Cell volume

187.8 ų

Atoms in the conventional cell

12 (Al 2, O 8, P 2)

Formula units Z

2

Pearson symbol

hP12 — hexagonal / trigonal, primitive lattice, 12 atoms per conventional cell

Symmetry operations

12 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 12 atoms drawn above are these sites multiplied by all 12 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

AB4C_hP12_186_b_bc_b-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP12, then the space-group number 186, then the Wyckoff letters occupied by each element in turn (Al: 2b; O: 2b; P: 2b; O: 6c). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Note: Tridymite 590K.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB4C_hP12_186_b_bc_b-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.