Bond
order: The number of covalent
bonds shared between two atoms. When the atoms share one
pair of electrons, they have a single
bond (bond
order = 1). A double
bond (bond
order = 2) consists of two electrons pairs, while sharing three
electron pairs results in a triple
bond (bond
order = 3). Bond
order can be fractional; for example, a partial
pi
bond resulting from resonance
has a bond
order between 1 and 2.
