Số oxi hóa của các nguyên tố trong các hợp chất, đơn chất và ion là:
\(\eqalign{& a)\,\,\mathop {{H_2}}\limits^{ + 1} \mathop S\limits^{ - 2} ,\,\,\mathop S\limits^0 ,\,\,\mathop {{H_2}}\limits^{ + 1} \mathop S\limits^{ + 4} \mathop {{O_3}}\limits^{ - 2} ,\,\,\mathop {{H_2}}\limits^{ + 1} \mathop S\limits^{ + 6} \mathop {{O_4}}\limits^{ - 2} ,\,\,\mathop S\limits^{ + 4} \mathop {{O_2}}\limits^{ - 2} ,\,\,\mathop S\limits^{ + 6} \mathop {{O_3}}\limits^{ - 2} . \cr& b)\,\,\mathop H\limits^{ + 1} \mathop {Cl}\limits^{ - 1} ,\,\,\mathop {{H_2}}\limits^{ + 1} \mathop {Cl}\limits^{ + 1} \mathop O\limits^{ - 2} ,\,\,\mathop {Na}\limits^{ + 1} \mathop {Cl}\limits^{ + 1} \mathop O\limits^{ - 2} ,\,\,\mathop H\limits^{ + 1} \mathop {Cl}\limits^{ + 7} \mathop {{O_4}}\limits^{ - 2} . \cr& c)\,\,\mathop {Mn}\limits^{ + 7} \mathop {O_4^ - }\limits^{ - 2} ,\,\,\mathop S\limits^{ + 6} \mathop {O_4^{2 - }}\limits^{ - 2} ,\,\,\mathop N\limits^{ - 3} \mathop {H_4^ + }\limits^{ + 1} ,\,\,\mathop {Cl}\limits^{ + 7} \mathop {O_4^ - }\limits^{ - 2} . \cr} \)
