Hydration Shell

Definition

The tight, shifting shell of water molecules that reorganizes around a separated ion, creating local order that stabilizes the dissolved species.

As a mineral dissolves, the ordered lattice gives way to ions each wrapped in a shell of oriented water molecules. The formation of these shells releases hydration energy that competes with the lattice energy holding the crystal together. The net of these two energies decides whether a substance dissolves or refuses to. It is the molecular picture of what dissolution actually produces.

Related concepts

Polarity · Hydration Energy · Entropy

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Part of The Blueprint of Water · 🧪 chemistry