Fluorapatite [Ca₅F(PO₄)₃, H5₇]

Unit cell

Lattice constants

a = 9.397 Å, b = 9.397 Å, c = 6.878 Å; α = 90.00°, β = 90.00°, γ = 120.00°

Cell volume

526.0 ų

Atoms in the conventional cell

42 (F 2, Ca 10, O 24, P 6)

Formula units Z

2

Pearson symbol

hP42 — hexagonal / trigonal, primitive lattice, 42 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 42 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

A5BC12D3_hP42_176_fh_a_2hi_h-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol hP42, then the space-group number 176, then the Wyckoff letters occupied by each element in turn (F: 2a; Ca: 4f; Ca: 6h; O: 6h; O: 6h; P: 6h; O: 12i). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ca₅OH(PO₄)₃ (hydroxylapatite), Ca₅Cl(PO₄)₃ (chlorapatite), Ca₅F(SiO₄)₃, Eu₅F(SiO₄)₃, CaDy₄(SiO₄)₃O, CaEr₄(SiO₄)₃O, CaNd₄(SiO₄)₃O, CaGd₄(SiO₄)₃O, CaSm₄(SiO₄)₃O, CaY₄(SiO₄)₃O, CaYb₄(SiO₄)₃O <!--beginning with an

Note: H5₇, Fluorapatite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A5BC12D3_hP42_176_fh_a_2hi_h-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.