An example of a molecular solid is sucrose.Ĭovalent-network (also called atomic) solids-Made up of atoms connected by covalent bonds the intermolecular forces are covalent bonds as well. Characterized by low melting points and flexibility and are poor conductors. Molecular solids-Made up of atoms or molecules held together by London dispersion forces, dipole-dipole forces, or hydrogen bonds. An example of an ionic solid is table salt, NaCl. They’re characterized by very high melting points and brittleness and are poor conductors in the solid state. Ionic solids-Made up of positive and negative ions and held together by electrostatic attractions. There are four types of crystalline solids: Common examples of this type of solid are glass and plastics. Though their molecules are close together and have little freedom to move, they are not arranged in a regular order as are those in crystalline solids. Amorphous solids do not have much order in their structures. The other main type of solids are called the amorphous solids. The smallest repeating pattern of crystalline solids is known as the unit cell, and unit cells are like bricks in a wall-they are all identical and repeating. Crystalline solids are those in which the atoms, ions, or molecules that make up the solid exist in a regular, well-defined arrangement. There are two main categories of solids-crystalline solids and amorphous solids. Solids have definite shapes and definite volumes and are not compressible to any extent. In fact, these forces are so strong that particles in a solid are held in fixed positions and have very little freedom of movement. Solids are generally held together by ionic or strong covalent bonding, and the attractive forces between the atoms, ions, or molecules in solids are very strong. Solid molecules simply vibrate and rotate in place rather than move about. As you should remember from the kinetic molecular theory, the molecules in solids are not moving in the same manner as those in liquids or gases.
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