There exist crystalline and amorphous solids. The crystals are characterised by the space periodicity in the distribution of atom equilibrium positions. In amorphous solids, the atoms oscillate around randomly distributed points. The steady state of a solid is the crystalline one.

There can be solids with ionic, covalent, metallic and other types of atomic bonds. Electrical and some other properties of solids are mainly controlled by the nature of how outer electrons of its atoms move. In terms of electrical properties, solids are divided into dielectrics, semiconductors, and conductors; in terms of magnetic properties, the solids can be diamagnets, paramagnets, and magnetically ordered solids.

The studies of the properties of solids were joined together in a large field, called solid state physics, as its development is encouraged by technology. In turn, solid state physics was divided into a number of areas due to a specific object of research (physics of metals, semiconductor physics, physics of magnets, etc.) or a method of study (X-ray structural analysis, radiofrequency spectroscopy, etc.) or properties (mechanical, thermal, etc.).