|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 base→Lewis 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.|
|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.