carbyne

noun3

1. •
   The linear carbon allotrope, composed of alternating (1) triple and single bonds [ ...–C≡C–C≡C–... ] or (2) double bonds [ ...=C=C=C=... ].
2. •
   Linear acetylenic carbon, a form of the linear carbon allotrope consisting of the form with alternating single- and triple-bonded carbons [ ...–C≡C–C≡C–... ].
3. •
   The trivalent radical R-C⋮ or any of its hydrocarbyl derivatives.