Tremolite (Ca₂Mg₅Si₈O₂₂(OH)₂ S4₂)

Unit cell

Lattice constants

a = 9.836 Å, b = 18.045 Å, c = 12.288 Å; α = 90.00°, β = 155.47°, γ = 90.00°

Cell volume

905.4 ų

Atoms in the conventional cell

82 (Mg 10, Ca 4, H 4, O 48, Si 16)

Formula units Z

2

Pearson symbol

mC82 — monoclinic, base-centred lattice, 82 atoms per conventional cell

Symmetry operations

8 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 82 atoms drawn above are these sites multiplied by all 8 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

A2B2C5D24E8_mC82_12_h_i_agh_2i5j_2j-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol mC82, then the space-group number 12, then the Wyckoff letters occupied by each element in turn (Mg: 2a; Mg: 4g; Ca: 4h; Mg: 4h; H: 4i; O: 4i; O: 4i; O: 8j; O: 8j; O: 8j; O: 8j; O: 8j; Si: 8j; Si: 8j). Two structures with the same label are the same arrangement with different cell parameters or coordinates.

Other compounds with this structure

Ca₂H₂(Mg_{5-x}, Fe_{x})O₂₄Si₈, Ca₂F₂Mg₅O₂₂Si₈ <!--beginning with an

Note: S4₂, Tremolite.

Source

Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry A2B2C5D24E8_mC82_12_h_i_agh_2i5j_2j-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.