Study of the kinetics of the triiodide equilibrium (CAT#: STEM-AC-0074-WXH)

Introduction

In chemistry, triiodide usually refers to the triiodide ion. This anion, one of the polyhalogen ions, is composed of three iodine atoms. It is formed by combining aqueous solutions of iodide salts and iodine. Some salts of the anion have been isolated, including thallium triiodide and ammonium triiodide. Triiodide is observed to be a red colour in solution.
The triiodide ion is the simplest polyiodide; several higher polyiodides exist. In solution, it appears yellow in low concentrations, and brown at higher concentrations. The triiodide ion is responsible for the well-known blue-black color which arises when iodine solutions interact with starch. Iodide does not react with starch; nor do solutions of iodine in nonpolar solvents.