Sec 1 S Structure and Properties ■The two pi bonds are unhybridized p overlaps at 90 which blend into a cylindrical shape. Ho bond 6bond o bond H overlap of p orbitals cylinder of electron density EPM of acetylene Copyright2010 Pearson Prentice Hall,Inc. Sec 1 Structure and Properties ◼The two pi bonds are unhybridized p overlaps at 90 , which blend into a cylindrical shape