In organic chemistry, a carbyne is a general term for any compound whose molecular structure includes an electrically neutral carbon atom with three non-bonded electrons, connected to another atom by a single bond. A carbyne has the general formula R-C3•, where R is any monovalent group and the superscript 3 indicates the three unbounded valences. Carbynes are named after the simplest such compound, HC3•, the methylidyne radical or (unsubstituted) carbyne. Bulk carbyne (−C≡C−)n is also called linear acetylenic carbon.