Aromatic hydrocarbons are a special class of organic compounds that contain one or more benzene rings in their structure. These rings are made up of carbon atoms arranged in a hexagonal shape, with alternating double bonds, giving them unique stability and chemical properties. Common examples include toluene and naphthalene, which are used in various industrial applications and products. These compounds are known for their distinct scents, which is where the term "aromatic" comes from. However, some aromatic hydrocarbons, like benzene, can be harmful to health and the environment, making it important to handle them with care.