Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay
Zunyite Al13Si5O20(OH,F)18Cl is an aluminosilicate with hydroxyl and halogens. It is remarkable because it contains units of 5 silica tetrahedra (pentamers).
At top, above, is one of the silica pentamers. It consists of a central tetrahedron with additional tetrahedra joined to each vertex.
At bottom, above are clusters of aluminum polyhedra (green). There is a central tetrahedrally coordinated aluminum, with each vertex joined to three octahedra. At left bottom is a perspective view and at right a transparent view. The aluminum atoms are at the vertices of a distorted cuboctahedron (outlined in red).
Zunyite has tetrahedral symmetry. Above: view down one of the isometric axes. Red are hydrogen atoms in hydroxil ions. Silica units are blue, aluminum are green.The vertices in the aluminum polyhedra may be occupied by oxygen, hydroxyl or halogens.
View along a unit cell diagonal.
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Created 22 April 2013, Last Update