Geology Reference
In-Depth Information
( ) Kaolinite
a
Tetrahedral
sheet
1:1 layer
7.2 Å thick
Octahedral
sheet
Basal oxygen plane
Silicon plane
Octahedral cation plane
Octahedral anion plane
( ) Illite
b
2:1 layer
9.4 Å thick
( ) Smectite
c
2:2 layer
14.4 Å thick
Figure 3.1
Clay mineral structure. (a) Kaolinite, a 1 : 1 dioctahedral layer silicate. (b) Illite, a 2 : 1 layer silicate,
consisting of one octahedral sheet with two flanking tetrahedral sheets. (c) Smectite, a 2 : 2 layer silicate, consisting
of 2 : 1 layers with octahedral sheets between. Å stands for an angstrom, a unit of length (1Å
10
−
8
=
cm).
Source:
After Taylor and Eggleton (2001, 59, 61)
