the ccc bond angle in allene (h2ccch2) is
Allene The central carbon atom of allene forms two sigma bonds and two pi bonds. The central carbon is sp-hybridized, and the two terminal carbon atoms are sp2-hybridized. The bond angle formed by the three carbon atoms is 180Â°, indicating linear geometry for the carbon atoms of allene. It can also be viewed as an "extended tetrahedral" with a similar shape to methane.