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CH3041
CATION EXCHANGE I
If an atom is substituted by an atom of lower oxidation number n+ then a net -ve charge will arise in a mineral. eg. Mg2+ replaces Al3+
Exchangeable ions are those which are held in the material by weak electrostatic forces.
eg1. the interlayer space in smectite clays.
eg2. the
surface edge
sites where
cations or
anions correct
the charge
imbalance.
equilibrium