H2O\mathrm{H}_{2} \mathrm{O}H2O
H3O+\mathrm{H}_{3} \mathrm{O}^{+}H3O+
H+\mathrm{H}^{+}H+
SO42−\mathrm{SO}_{4}^{2-}SO42−
H2SO4\mathrm{H}_{2} \mathrm{SO}_{4}H2SO4