Solvation: definition in chemistry
Solvation: The process of solvent molecules surrounding and interacting with dissolved particles such as ions or molecules.
When a substance dissolves, its particles separate and each becomes surrounded by a shell of solvent molecules attracted to it. Polar solvents solvate ions and polar molecules well, while nonpolar solvents solvate nonpolar molecules, which is the idea behind like dissolves like. The energy released by solvation helps pay for pulling the solute apart, and the balance decides whether dissolving releases or absorbs heat.
Examples
- Salt dissolving in water as water molecules surround each Na⁺ and Cl⁻ ion
- Sugar dissolving in tea as water molecules hydrogen-bond to it
- Grease dissolving in hexane, a nonpolar solvent
- Lithium ions surrounded by solvent molecules in a lithium-ion battery
On the periodic table
Ions get larger down a group, and larger ions with the same charge are solvated less strongly, so Li⁺ holds solvent molecules more tightly than Na⁺ or K⁺.