Iodine is a diatomic molecule and a member of the halogen group in the periodic table. It is a dark gray or purple-black solid at room temperature, sublimating to a violet gas. Iodine is essential for the synthesis of thyroid hormones, which regulate metabolism in humans and other animals. In culinary applications, iodine is often added to table salt to prevent iodine deficiency, which can lead to thyroid-related health issues. It has antiseptic properties and is used in various medical applications. Iodine's sensory characteristics include a strong, pungent odor, and it is known for its distinctive color in solution. Its role in food and health is significant, as it is crucial for proper thyroid function.