Pi Bond - Special Cases

Special Cases

Pi bonds do not necessarily connect a pair of atoms that are also sigma-bonded.

In certain metal complexes, pi interactions between a metal atom and alkyne and alkene pi antibonding orbitals form pi-bonds.

In some cases of multiple bonds between two atoms, there is no sigma bond at all, only pi bonds. Examples include diiron hexacarbonyl (Fe2(CO)6), dicarbon (C2), and the borane B2H2. In these compounds the central bond consists only of pi bonding, and in order to achieve maximum orbital overlap the bond distances are much shorter than expected.

Read more about this topic:  Pi Bond

Famous quotes containing the words special and/or cases:

    I think those Southern writers [William Faulkner, Carson McCullers] have analyzed very carefully the buildup in the South of a special consciousness brought about by the self- condemnation resulting from slavery, the humiliation following the War Between the States and the hope, sometimes expressed timidly, for redemption.
    Jimmy Carter (James Earl Carter, Jr.)

    For the most part, we are not where we are, but in a false position. Through an infirmity of our natures, we suppose a case, and put ourselves into it, and hence are in two cases at the same time, and it is doubly difficult to get out.
    Henry David Thoreau (1817–1862)