What vibrating particles don't have enough energy to move out of position?

What is a solid?

blank sellers have particles arranged in geometric patterns

The particles that do not have enough energy to move out of position are known as "fixed" or "stationary" particles. These particles can be found in solid materials. When a material is in a solid state, its particles are closely packed together, and they vibrate around their equilibrium positions due to thermal energy. However, the amount of energy is not sufficient to overcome the forces of attraction holding the particles together, preventing them from moving freely. This is what gives solids their shape and rigidity.