bonding number
The bonding number \(n\) of a @S05706@ is the sum of the total number of bonding equivalents (@V06588@ bonds) of that @S05706@ to adjacent skeletal atoms in a @P04405@, if any, and the number of attached hydrogen atoms, if any. Examples: SH2: for S, \(n=2\); SH6: for S, \(n=6\).
Blue Book Guide, p. 21 [Terms] [Book]
See also:
PAC, 1984, 56, 769. (Treatment of variable valence in organic nomenclature (lambda convention) (Recommendations 1983)) on page 774 [Terms] [Paper]