Structure of the layered silicates
Transcript of Structure of the layered silicates
Clay and Clay Minerals:
Hectorite
Festkörperpraktikum
Modul AC III 2014
What is Clay? : (Ton)
•Designation of the smallest particle size fraction of soil
(irrespective of the mineral composition)
•Mineral name for natural, earthy, fine-grained material
Main component: clay minerals (layered silicates)
Structure of the layered silicates
• 2D Structure (layered structure)
• anisotropic particles
• nanocrystalline
a) Brucite type octahedral (trioctahedral;CdI2-Typ; Brucite: Mg(OH)2)
b) Tetrahedral layer
c) Gibbsite type octahedral (dioctahedral; BiI3-Typ Gibbsite: Al(OH)3)
a b c
Hectorite
Saponite
Vermiculite
y)x(
210
.
4
.
yy3
.
2
n
nx (F)OSi LiMg OHZ
TetOktZwi
z)x(
210
.
z4z
.
3
.
2
n
nx (F)OSiAl Mg OHZ
TetOktZwi
y)zx(
210
.
z4z
.
yy3
.
2
n
nx (F)OSiAl AlMg OHZ
TetOktZwi
Structure of the layered silicates
Classification of layered silicates
Morphology of layered silicates
Importance for Humanity
Effect of weather
(e.g layered silicate)
everywhere
•Soil (30-40%)
•Mud
•Sediments
2D Structure
anisotropic particles
nanocrystalline
Special Material Properties
Plasticity
Thixotropy
Ad- and Absorption
Cation Exchange •Agriculture
•Construction
•Industry
source properties
Reactivity of the edge
Thixotropic structures by house of cards
Applications
• Thixotropic additives :
Colors,
Drilling emulsions ...
• Adsorbents :
Cat Litter ,
Packaging...
• Carrier materials
• Additives for composite materials
Construction materials,
Reactions in the interlayer space
Analysis - Powder Diffraction
d [001] = 2·d [002] = 3·d [003] = l·d [00l]
Integrity of the series:
X
SD100CV
CV: Coefficient of Variation
CV > 0,75 %: random inter
stratified
(different d-spacing along
stacking)
CV < 0,75 %: ordered system
(ordered stacking sequence)
Analysis - Powder Diffraction
As Fe-bipy-hectorite with Na-hectorite
Fe-bipy hectorite d001 at about 1.8 nm,
the Na-hectorite-d001 is about 1.2 nm
The 001 reflection is usually the strongest reflection and largest d value
Viel Erfolg!