In a solid, particles are closely packed together in a fixed arrangement. The attractive forces between them are strong, which keeps the particles in a rigid structure. Generally, the distance between the particles in a solid is very small, often just a few atomic diameters apart.
Despite being tightly packed, particles in a solid do have some movement. They primarily vibrate in place rather than move freely as they do in liquids or gases. This vibrational motion occurs due to the thermal energy of the particles. As temperature increases, so does this vibrational energy, causing the particles to move more vigorously, although they remain constrained in their specific positions within the solid lattice.