$\overset{X}{\mathop{I}}\,\overset{-1}{\mathop{Cl}}\,:\,\,X-1\,=0\,\,\,\,\Rightarrow X=+1$

$\overset{+1}{\mathop{H}}\,\overset{X}{\mathop{I}}\,:\,\,\left( +1 \right)+X=0\,\,\,\Rightarrow X=-1$

${{\overset{X}{\mathop{I}}\,}_{2}}\,\,:\,\,X=0$

$\overset{+1}{\mathop{H}}\,\overset{X}{\mathop{I}}\,{{\overset{-2}{\mathop{O}}\,}_{4}}\,\,:\,\,\left( +1 \right)+X+4\left( -2 \right)=0\,\,\,\Rightarrow \,\,\,X=+7$

આથી, આયોડિનના ઓ.આંકનો ઘટતો ક્રમ નીચે પ્રમાણે થાય.

$HI{O_4}\,\,\, > \,\,ICl\,\,\, > \,\,\,{I_2}\,\,\, > \,\,\,HI$