When a particular oxidation state becomes less stable relative to other
oxidation states, one lower, one higher, it is said to undergo disproportionation For example, manganese (VI) becomes unstable relative to manganese(VII) and
manganese (IV) in acidic solution 3 Mn
VIO4 
2– + 4 H
+ ® 2 Mn
VIIO
–
4 + Mn
IVO2 + 2H2O
Example 4 9
Example 4