What is the Difference Between Iodide and Triiodide?

The main difference between iodide and triiodide lies in the number of iodine atoms and their charges:

• Iodide: Iodide (I⁻) is a simple monatomic anion, consisting of a single iodine atom with a -1 charge. It is one of the anions of iodine and is often found in aqueous solutions.
• Triiodide: Triiodide (I⁻³) is a polyatomic anion composed of three iodine atoms, also with a -1 overall charge. It is formed by combining aqueous solutions of iodide salts and iodine.

Both iodide and triiodide are anions of iodine and carry a negative charge. They are often found together in aqueous solutions, existing in equilibrium with the diiodide anion. In low concentrations, triiodide solutions appear yellow, but they turn red-brown at high concentrations.

Comparative Table: Iodide vs Triiodide

The key difference between iodide and triiodide is that iodide is a single iodine atom with a -1 charge, whereas triiodide is a combination of three iodine atoms with a -1 overall charge. Here is a table summarizing the differences between iodide and triiodide:

Both iodide and triiodide are anions of iodine and are negatively charged. They are commonly found in solutions like Lugol's iodine solution and tincture of iodine solution.