Answer : Broadly solids are divided into three categories;
i) Crystalline solids have a regular definite structure, in which the particles pack in a repeating pattern from one edge of the solid to the other.
ii) Amorphous solids have a random structure, with little unorganized pattern long-range order.
iii) Polycrystalline solids are those where an aggregate which consists of a large number of small crystals or grains in which the structure is regular, but the crystals or grains are found to be arranged in a random fashion.
Also solids can be divided into 3 more categories according to their bonds;
i) Covalent solids, like diamond, which forms crystals that can be viewed as a single giant molecule made up of an almost endless number of covalent bonds.
ii) Ionic solids are basically salts, such as NaCl, in which the molecules are held together by the strong force of attraction between ions of opposite charge.
iii) Metallic solids are found in metals which have the force of attraction between atoms of metals, such as copper and aluminum, or alloys, such as brass and bronze, are metallic bonds.
