Illustrated Glossary of Organic Chemistry

Arrows: Fundamental arrow types denoting different chemical processes or phenomena.


Reaction proceeds from reactants (on left) to products (on right).

Indicates electron donation from a Lewis base to a Lewis acid in a Lewis acid-Lewis base adduct: Lewis baseLewis acid. This usage not common.

Indicates a pi bond interaction between elements not in the same period (row) of the periodic table; a very polar pi bond. For example S→O in a sulfoxide. The arrows points from the less electronegative element to the more electronegative element. This usage is not common.

Equilibrium. Shafts lengths are not meant to imply Keq ≠ 1, or stated otherwise.

The structures on either end of the arrow are resonance contributors.

Curved arrow indicating shift of an electron pair. Note this arrow has two barbs on the pointy end.

Curved arrow indicating shift of a single electron. Note this arrow has one barb on the pointy end.

Photon added.

Retrosynthesis arrow. Designates that the species of the left is derived from the species on the right.

Bond dipole arrow. The arrow head points to the more electronegative atom (the δ- atom); the crossed end of the arrow lies above the more electropositive atom (the δ+ atom).

The species to the left of this arrow leaves the reaction mixture as a precipitate.

The species to the left of this arrow leaves the reaction mixture as a gas.

A electron pair in an orbital. A single arrow (pointing up or down) can be used to denote a single electron in an orbital.