Difference between Double Salt and Complex Salt:
When we talk about salts, we are generally referring to a compound that consists of cations and anions held together by ionic bonds. However, not all salts are created equal. There are two primary types of salts – double salts and complex salts. While both of these salts contain two or more ions, they differ when it comes to their structure and properties. In this article, we will explore the difference between double salt and complex salt.
Double Salt:
Double salt is a type of salt that is formed by a combination of two simple salts. In a double salt, the two substances are present in their ionised state and are held together by ionic bonds. Double salts only exist as a single crystalline compound and can be broken down into their constituent ions by dissolving in water. Common examples of double salts include alum, which is a combination of potassium sulfate and aluminum sulfate, and Mohr’s salt, which is a combination of ferrous sulfate and ammonium sulfate.
Double salts have a unique property called “isomorphism”, where two or more substances may crystallize together in the same crystal structure. The phenomenon of isomorphism is particularly useful in improving the stability of some medicines, where double salts are often used as active ingredients.
Complex Salt:
Complex salt is a type of salt that is formed by a combination of a metal ion and a complex ion. A complex ion is a type of ion that is formed when a simple ion binds to one or more other molecules or ions. In a complex salt, the metal ion is held together with the complex ion by covalent bonds. Unlike double salts, complex salts can exist as multiple crystalline compounds, which can differ in their physical properties.
Common examples of complex salts include sodium tetraphenylborate, which is formed by combining sodium ions with the tetraphenylborate anion, and potassium sodium tartrate, which is formed by combining potassium ions with the tartrate anion. Complex salts are often used in the preparation of some organic compounds and can also be used as catalysts in chemical reactions.
Conclusion:
In summary, double salts are formed by a combination of two simple salts, while complex salts are formed by a combination of a metal ion and a complex ion. Double salts are held together by ionic bonds, while complex salts are held together by covalent bonds. Double salts exist as a single crystalline compound, while complex salts can exist as multiple crystalline compounds. Understanding the difference between these two types of salts is important in many industries, including pharmaceuticals and fine chemicals.
Table difference between double salt and complex salt
| Property | Double Salt | Complex Salt |
|---|---|---|
| Definition | A compound formed by the combination of two simple salts. | A compound formed by the combination of a simple salt with a complexing agent. |
| Composition | Contains two different cations and two different anions. | Contains a simple cation, a complex anion, and sometimes a simple anion. |
| Structure | Consists of discrete, separate ions in a fixed stoichiometric ratio. | Consists of tightly bound ions that form a complex unit with a definite and reproducible stoichiometry. |
| Formation | Formed by the reaction of two simple salts in a specific stoichiometric ratio. | Formed by the reaction of a simple salt with a complexing agent, which forms a stable coordination compound with the simple ion. |
| Solubility | Usually less soluble in water than either of the simple salts that make it up. | May be more soluble in water than the simple salt that it is derived from due to the formation of a complex ion. |