Structural Proof for the First Dianion of a Polychloride: Investigation of [Cl8]2−

The polychloride salt [CCl(NMe2)2]+2[Cl8]2− was synthesized and crystallized in the ionic liquid [BMP]OTf. The compound was fully characterized by Raman spectroscopy as well as X-ray single-crystal structure determination, and represents the first example of a polychloride dianion to be described. Detailed gas-phase and solid-state calculations concerning the nature of the bonding situation were also performed.