Ferroin

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Ferroin
Names
IUPAC name
1,10-phenanthroline iron(II)
Other names
1,10-Phenanthroline iron(II) sulfate complex
Ferroin indicator solution
MFCD00036428
Properties
C36H24FeN62+ (cation)
[Fe(o-phen)3]SO4 (sulfate)
Molar mass 596.27 g/mol (cation)
692.5 g/mol (sulfate)
Appearance Blood-red liquid (solution)
Odor Odorless
Density 0.999 g/mL at 25 °C (0.1% solution)
Melting point Decomposes above 60 °C (solution)
Boiling point Decomposes
Soluble
Solubility Insoluble in hydrocarbons
Vapor pressure ~0 mmHg
Hazards
Safety data sheet Sigma-Aldrich (0.1 % solution)
Related compounds
Related compounds
Phenanthroline
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.

Properties

Chemical

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.

Physical

The aq. solution of ferroin is a dark red liquid, odorless, which changes color in oxidizing medium.

Availability

Ferroin is sold by chemical suppliers.

Preparation

Ferroin sulfate may be prepared by mixing an aq. solution of phenanthroline with one of iron(II) sulfate.

3 o-phen + Fe2+ → [Fe(o-phen)3]2+

Projects

Handling

Safety

Ferroin has low toxicity, though it may be irritant. It tens to stain, which are not very easy to remove.

Storage

In closed dark amber bottles, away from oxidizing agents and acids.

Disposal

Ferroin should be strongly diluted before being poured down the drain.

References

Relevant Sciencemadness threads