Ferroin is the chemical compound with the formula [Fe(o-phen)3]SO4, where o-phen is an abbreviation for 1,10-phenanthroline.
This coordination compound
is used as an indicator in analytical chemistry
. The active ingredient is the [Fe(o
ion, which is the redox-active chromophore
. Ferroin includes other salts of the same basic dication.
Its redox potential is +1,06 volts in 1M H2SO4.
Preparation of reagent
A solution of 1.485 g 1,10-phenanthroline monohydrate is added to a solution of 695 mg FeSO4
O in water, and the resulting red solution is diluted to 100 mL.