... [ F o > 4σ F ]. The structure is the same as that of other members of the ardennite group. It contains chains of edge-sharing Mn 3+ and Al octahedra extending along the b axis, which are linked into a framework by sharing corners with SiO 4 tetrahedra and with Si 3 O 10 tetrahedral groups. Within...

... the conditions for the interlayer coordination (which must occur between two facing “hexagonal” rings of tetrahedra), the ± b /3 slips in the n -th layer require the same slips for the layer stacked immediately above it. Consequently, in a dioctahedral mica the position of a filled M site comes to correspond...

... Ca 0.29 □ 0.31 ). The X -site occupancy allows conjecture on the degree of order of B atoms in individual six-membered rings of tetrahedra; two different schemes of order are possible. The amount of [4] B in the optimized formula ( [4] B = 1.06 apfu ) allows, on average, approximately one [4...

... leadhillite including three distinct types of layers. Layer A includes sulphate tetrahedra, Layer B is composed of Pb and OH, while Layer C is composed of Pb and CO 3 with topology identical to that in cerussite. In both macphersonite and leadhillite these layers are stacked along [010] as …BABCCBABCC...

... edges to form rutile-like chains, three of which join by the sharing of octahedral edges to form triple chains that are parallel to [001]. The MoO 4 tetrahedra are linked to either side of the triple chain of Cu (super 2+) phi 6 octahedra by the sharing of two vertices per tetrahedron, and the resulting...