The two terminal carbons are sp2 hybridised. The central carbon is sp hybridised. The remaining two p orbitals on the central carbon overlap with the p orbitals on the terminal carbons to produce two pi bonds. These pi bonds are perpendicular so the molecule is twisted.
Click the images to display the orthogonal p orbitals that make up the two pi-bonds and the resulting pi-orbitals.
Use the buttons to display the orthogonal pi orbitals individually and together. Note that the molecular orbitals are not completely localised.
Explore bonding orbitals in other small molecules
Hydrogen | Fluorine | Methane | Ethylene | Acetylene | Allene | Formaldehyde | Benzene