2 I
– + S2O8
2– ® I2 + 2 SO4
2–
An explanation of this catalytic action can be given as:
2 Fe
3+ + 2 I
– ® 2 Fe
2+ + I2
2 Fe
2+ + S2O8
2– ® 2 Fe
3+ + 2SO4
2–
Interstitial compounds are those which are formed when small atoms
like H, C or N are trapped inside the crystal lattices of metals They are
usually non stoichiometric and are neither typically ionic nor covalent,
for example, TiC, Mn4N, Fe3H, VH0 56 and TiH1 7, etc