Halogen compounds are chemical substances that contain at least one halogen element, which includes fluorine, chlorine, bromine, iodine, and astatine. These compounds can be found in various forms, such as gases, liquids, or solids, and they often exhibit unique properties, including high reactivity and the ability to form salts when combined with metals. Common examples of halogen compounds include sodium chloride (table salt), chlorofluorocarbons (CFCs), and hydrogen fluoride. These compounds play significant roles in everyday life, from household products to industrial applications, and are also important in environmental chemistry and the study of organic compounds.