LAUSR

We are writing in response to Rzepa’s theoretical analysis of the generation of C2, which cites our recent paper describing the first chemical synthesis of C2 (ref. 1). Rzepa suggests on the basis of several in silico approaches that the formation of free C2 from alkynyl-λ3iodane and fluoride ion would be prohibitively endo-energetic. He proposes three possible explanations of the apparent discrepancy between these theoretical calculations and our experimental findings, of which one is that some species other than C2 is actually formed. As our original paper was primarily experimental, describing room-temperature chemical synthesis of C2 and the first bottom-up chemical synthesis of nanocarbons from C2, we should like to respond to the latter point. We believe that the evidence presented in our paper for the generation of C2 itself is compelling1. In particular, the connected-flask, solvent-free experiment clearly supports the generation of free C2 gas, for the following reasons: