The mica layer and its constituents

plane of the interlayer cations (also these cations as such). 

plane of the apical oxygen atoms of the tetrahedra this plane, contains approximately also OH groups and, depending on the kind of mica, F and, less frequently. Cl and S. 

the two translationally independent tetrahedral sites within a T sheet MXJs/TlfT ). the three translationally independent octahedral sites within an O sheet 

Y plane of the octahedral cations (whose coordination polyhedra are however not 

M the entire mica layer (T-O-T). There are two types Ml and M2 depending on the location (Ml vs. M2/M3) of the origin of the O sheet. Standard character M indicates layer, italics M indicates cation sites. 

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