What is the Difference Between Iodine and Iodide?

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The main difference between iodine and iodide lies in their chemical forms and how they occur in nature:

  • Iodine: Iodine is a chemical element found on the periodic chart and consists of two atoms of iodine bonded together. This molecular form is not found in nature. In its elemental state, iodine is highly corrosive and should not be ingested or applied directly to skin or tissue.
  • Iodide: Iodide is the ionic state of iodine, occurring when iodine bonds with another element, such as potassium or sodium. Iodide is found in nature, in seaweed, mineral deposits, and iodized salt (either as potassium iodide, potassium iodate, sodium iodide, or sodium iodate). Iodide is quickly and almost completely absorbed in the stomach and duodenum, making it suitable for ingestion.

In summary, iodide is a safe and absorbable form of iodine that occurs naturally in the environment, while elemental iodine is a highly corrosive substance that should not be ingested or applied directly to skin or tissue.

Comparative Table: Iodine vs Iodide

Here is a table highlighting the differences between iodine and iodide:

Iodine Iodide
Iodine is a chemical element with the atomic number 53 and symbol I. Iodide is the ion form of iodine, occurring when iodine bonds with another element, such as potassium.
Iodine is a naturally occurring element necessary for human growth and metabolic function. Iodide is a salt form of iodine, which can be found in seaweed sources and mineral deposits.
Elemental iodine is a lustrous, metallic-grey solid at room temperature. Iodide can be ingested or applied topically, such as with povidone iodine, an iodide.
Iodine is highly corrosive and can cause severe damage to tissue on contact. Iodides represent a safe form of iodine for ingestion.

In summary, iodine is the element itself, while iodide is the ion form of iodine. Iodine is essential for human growth and metabolic function, but it is highly corrosive and cannot be ingested directly. Iodide, on the other hand, is a safe form of iodine that can be ingested or applied topically, making it suitable for various applications.