| IUPAC name
| Other names
1,10-Phenanthroline iron(II) sulfate complex
Ferroin indicator solution
| C36H24FeN62+ (cation)|
|Molar mass|| 596.27 g/mol (cation)|
692.5 g/mol (sulfate)
|Appearance||Blood-red liquid (solution)|
|Density||0.999 g/mL at 25 °C (0.1% solution)|
|Melting point||Decomposes above 60 °C (solution)|
|Solubility||Insoluble in hydrocarbons|
|Vapor pressure||~0 mmHg|
|Safety data sheet||Sigma-Aldrich (0.1 % solution)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Ferroin is the chemical compound with the formula [Fe(o-phen)3]SO4, where o-phen is an abbreviation for 1,10-phenanthroline, a bidentate ligand. The term "ferroin" is used loosely and includes salts of other anions such as chloride.
Ferroin is used as an indicator in analytical chemistry. The active ingredient is the [Fe(o-phen)3]2+ ion, which is a chromophore that can be oxidized to the ferric derivative [Fe(o-phen)3]3+. The potential for this redox change is +1.06 volts in 1 M H2SO4. It is a popular redox indicator for visualizing oscillatory Belousov–Zhabotinsky reactions.
Ferroin is suitable as a redox indicator, as the color change is reversible, very pronounced and rapid, and the ferroin solution is stable up to 60 °C.
The aq. solution of ferroin is a dark red liquid, odorless, which changes color in oxidizing medium.
Ferroin is sold by chemical suppliers.
- 3 o-phen + Fe2+ → [Fe(o-phen)3]2+
- Belousov–Zhabotinsky reaction
- Make fake blood
- COD titration indicator
Ferroin has low toxicity, though it may be irritant. It tens to stain, which are not very easy to remove.
In closed dark amber bottles, away from oxidizing agents and acids.
Ferroin should be strongly diluted before being poured down the drain.