NH₄H₂PO₄

Unit cell

Lattice constants

a = 7.500 Å, b = 7.500 Å, c = 7.549 Å; α = 90.00°, β = 90.00°, γ = 90.00°

Cell volume

424.6 ų

Atoms in the conventional cell

56 (N 4, P 4, H 32, O 16)

Formula units Z

4

Pearson symbol

tI56 — tetragonal, body-centred lattice, 56 atoms per conventional cell

Symmetry operations

16 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 56 atoms drawn above are these sites multiplied by all 16 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

A8BC4D_tI56_122_2e_b_e_a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol tI56, then the space-group number 122, then the Wyckoff letters occupied by each element in turn (N: 4a; P: 4b; H: 16e; H: 16e; O: 16e). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

NH₄H₂AsO₄ <!--beginning with an

Note: Paraelectric phase.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A8BC4D_tI56_122_2e_b_e_a-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.