Table 2.
Chemical composition, layer charge, unit cell dimensions, and exfoliation properties of Mg1−xAlx(OH)2(An−)x/n·mH2O with An− anions = Cl−, I−, CO32−, SO42−.
| Anion | Nom. Comp. x |
Exp. Comp. x |
Charge Density (102qe/Å2) |
a-Axis 1 (Å) |
d-Spacing (Å) |
c-Axis 2 (Å) |
End Turbidity (NTU) |
Degree of Exfoliation (%) | ||
|---|---|---|---|---|---|---|---|---|---|---|
| d 003 | d 006 | Freeze Dried | Pre-Treated | |||||||
| Cl− | 0.20 | 0.18 | 2.55 | 3.082 | 8.182 | 4.074 | 24.495 | |||
| Cl− | 0.25 | 0.25 | 3.16 | 3.066 | 8.026 | 3.999 | 24.036 | 24.304 | 810 | 15 |
| Cl− | 0.33 | 0.33 | 4.13 | 3.045 | 7.833 | 3.888 | 23.414 | |||
| I− | 0.20 | 0.20 | 2.55 | 3.070 | 8.600 | 4.292 | 25.776 | |||
| I− | 0.25 | 0.24 | 3.16 | 3.052 | 8.241 | 4.243 | 25.091 | 815 | 32 | |
| I− | 0.33 | 0.32 | 4.13 | 3.045 | ------ | ------ | ------- | |||
| CO32− | 0.20 | 0.20 | 2.55 | 3.077 | 8.021 | 3.987 | 23.993 | |||
| CO32− | 0.25 | 0.25 | 3.16 | 3.062 | 7.849 | 3.916 | 23.522 | 23.525 | 217 | 20 |
| CO32− | 0.33 | 0.33 | 4.13 | 3.043 | 7.639 | 3.800 | 22.861 | |||
| SO42− | 0.20 | 0.21 | 2.55 | 3.068 | 8.589 | 4.292 | 25.760 | |||
| SO42− | 0.25 | 0.26 | 3.16 | 3.050 | 8.746 | 4.364 | 26.213 | 33.569 | 1066 | 15 |
| SO42− | 0.33 | 0.34 | 4.13 | 3.029 | 8.843 | 4.414 | 26.510 | |||
1a = 2d110; 2 c = (3d003 + 6d006)/2.