Is solvated I3− angular?

In this communication, we address the question of the geometry of the ground state of the solvated triiodide anion from a theoretical perspective. We use a simple, physically motivated and transparent model comprising a tight-binding molecular orbital scheme, point charges and an Onsager reaction field to describe the anion and its liquid environment. We suggest the possibility of an angular I3− geometry originating from the coupling of a molecular dipole to the polarizable solvent once the strength of the reaction field exceeds a critical value. The theoretical results are compared to recent experimental findings.