Unimolecular Reaction

An elementary step in which only one reacting molecule participates.

Unit Cell

The basic repeating unit of the arrangement of atoms, molecules, or ions in a crystalline solid.

Unsaturated Hydrocarbons

Hydrocarbons that contain carbon-carbon double bonds or carbon-carbon triple bonds.

Unsaturated Solution

A solution that contains less solute than it has the capacity to dissolve.