Figure 1 Crystal structure of pyrosmalite-(Fe). The brucite-type layers are made of Fe1(O,Cl)6 (turquoise color; site symmetry [\overline{3}]m.), Fe2(O,Cl)6 (.2.), Fe3O6 (.2/m), and Fe4O6 (.m.) octahedra. For clarity, the average coordinates of OH1 and Cl1 were used to draw the figure. The SiO4 tetrahedral sheets consist of 12-, 6-, and 4-membered rings with a ratio of 1:2:3. The small white, blue, and green spheres represent hydrogen atoms H1, H2, and H3, respectively. The large red spheres represent the disordered Ow1 sites that are partially occupied by H2O molecules.  [article HTML]