Difference Between Iodine and Iodide

Iodine vs Iodide

Iodine and iodide variation can be understood very easily if one has basic understanding of chemistry. But there are many who are confused and use the two words interchangeably which is not correct. Iodine is a chemical compound that is purple in color whereas iodide is an ion and can not remain in free state implying it has to combine with a another element or elements to form a compound. Iodine is an element with high atomic number 53 and is represented by the symbol I where as iodide being an ion and is represented by 1-.

Iodine is from the family of halogens like fluorine and bromine and is found in diatomic state just like them. Iodide ion is largest ion in its family of halides like bromide and fluoride, because of which it forms weak compounds with other elements. The element iodine is very rarely found as it is chemically very reactive and combines with other compounds easily to form iodide compound.

Iodine as an element can not exist freely but combines with other elements like silver and sodium to form iodide salts, it also forms organic compounds like methyl iodide that are of industrial uses. Iodine is also used as disinfectant.

Iodine is in news lately because of a disease called goiter that occurs when there is a deficiency of Iodine in the body. To compensate for the deficiency of Iodine in the body, the body responds with an enlarged thyroid gland. T3 and T4 are the hormones that are considered beneficial to prevent this disease that has taken alarming proportions is some poor countries of the world.

Doctors caution people not to take the element Iodine orally as it is poisonous and can harm the person. It is the salts of Iodine such as Potassium Iodide that are helpful in treating this disease. Iodine transforms in to its salts and thus becomes iodized. It is in this iodized state that Iodine is beneficial as it can interact with other elements. KI is an important salt of Iodine that is of great significance for us. Iodine is in a stable form when it is present as KI. This stable Iodine helps our bodies to make thyroid hormones. Most of the stable Iodine is made available to the body through the food we eat. But when there is not enough Iodine in stable form in the foods we eat, there is a deficiency of iodine leading to a stage called goiter. To prevent goiter, it is essential to take KI in medicine form on the advice of health care professionals.


• Iodine is an important element from the family of halogens.

• Iodide is the ion of Iodine showing a valency of -2.

• Small amounts of stable Iodine are required by our bodies to make hormones necessary for our thyroid gland.

• Deficiency of stable iodine leads to a disease called goiter.

  • Blake Thacker

    Does anyone know if Nascent Iodine has a shelf life? As in how long does it stay magnetically charged? What form does it turn into after it loses it charge?