Double Salt
| Formula / Notation | Double salt = two salts crystallised together; e.g., FeSO₄·(NH₄)₂SO₄·6H₂O (Mohr's salt) |
|---|---|
| Also Known As | Double salt crystal, mixed salt, Mohr's salt type, alum type |
What is Double Salt?
A salt formed by the crystallization of two different simple salts in a fixed ratio from a common solution. Double salts dissociate completely in water to yield all the constituent ions. An example is alum, KAl(SO₄)₂·12H₂O.
Formula & Notation
Other Names / Synonyms: Double salt crystal, mixed salt, Mohr's salt type, alum type
Properties & Characteristics
Uses & Applications
Safety Information
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
Key Facts
Frequently Asked Questions
A salt formed by the crystallization of two different simple salts in a fixed ratio from a common solution. Double salts dissociate completely in water to yield all the constituent ions. An example is alum, KAl(SO₄)₂·12H₂O.
Mohr's salt is used as a primary standard in redox titrations (more stable than FeSO₄ alone against air oxidation). Alums are used in water purification and dyeing. Double salts provide convenient crystalline forms with improved stability for analytical and industrial applications.
Individual hazards depend on the constituent salts. Mohr's salt contains iron(II) and ammonium sulfate — relatively low toxicity but may irritate eyes and skin. Alums are of low toxicity. Handle as general laboratory reagents with standard PPE.
The formula or notation for Double Salt is: Double salt = two salts crystallised together; e.g., FeSO₄·(NH₄)₂SO₄·6H₂O (Mohr's salt)