I⁻, known as iodide, is the negatively charged ion of iodine. It is formed when iodine gains an electron, resulting in a stable configuration. Iodide is essential for human health, particularly for the production of thyroid hormones, which regulate metabolism. In nature, iodide is commonly found in seawater and certain minerals. It is also present in iodized salt, which is used to prevent iodine deficiency in populations. Iodide plays a crucial role in various biological processes and is important for maintaining overall health, especially in the thyroid gland.