Term: lambda
https://doi.org/10.1351/goldbook.L03418

Definition:
Signifies, with its superscript, the bonding number, i.e. the sum of the number of skeletal bonds to an atom and the number of hydrogen atoms associated with it in a parent hydride, real or hypothetical. Its usage in names of compounds is generally restricted to non-standard valence states.

Related Terms:
1) bonding number (http://doi.org/10.1351/goldbook.B00703).
2) parent hydride (http://doi.org/10.1351/goldbook.P04405).
3) valence (http://doi.org/10.1351/goldbook.V06588).

Source: PAC, 1984, 56, 769. 'Treatment of variable valence in organic nomenclature (lambda convention) (Recommendations 1983)' on page 774 (https://doi.org/10.1351/pac198456060769)

Citation: 'lambda' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.L03418

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