Structural linkage among Mica group silicates3D ModelNoAI
Structural linkage among Mica group silicates
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More model informationThe general formula of Micas can be written as: I2M4-6◻2-0T8O20A4, where:
- I : K or Na, but Cs, NH4, Rb, Ca, Ba and other cations may occur;
- M : Mg, Fe2+, Fe3+, Al, Li, but also Ti, Mn, Zn, Cr, V and other cations;
- ◻ : vacant;
- T : Si, Al, and more rarely Fe3+;
- A : (OH), F but can also be Cl, O and S.
The basic structural feature of mica is a composite layer in which a sheet of octahedrally coordinated M cations (mainly Al, Mg, Fe) is sandwiched between two identical and opposing sheets of linked (Si,Al)O4 tetrahedra. In the micas, these layers (sometimes referred to as TOT or 2:1 layers) have a net negative charge which is balanced by planes of I cations (commonly K, Na - in12-fold coordination) lying between them.
Note: The color code used in these models is CPK.
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Website: http://geology.uaic.ro/muzee/mineralogie/
Concept & 3D-modelling by dr. Andrei Ionut APOPEI
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