Term: functionality, \(f\)
https://doi.org/10.1351/goldbook.FT07505

Definition:
Number of covalent bonds that a monomer molecule or monomeric unit in a macromolecule or oligomer molecule can form with other reactants.

Notes:
0) There are no monofunctional monomers.
1) If f = 2, a @L03546@ macromolecule or a @M03662@ can be formed.
2) If f > 2, a branch point can be formed leading to a branched macromolecule, a @NT07562@ or a micronetwork.
3) Ethene and ethylene glycol are examples of difunctional monomers, glycerol is an example of a trifunctional @M04017@, and divinylbenzene and pentaerythritol are examples of tetrafunctional monomers.

Related Terms:
1) linear chain (http://doi.org/10.1351/goldbook.L03546).
2) macrocycle (http://doi.org/10.1351/goldbook.M03662).
3) network (http://doi.org/10.1351/goldbook.NT07562).
4) monomer (http://doi.org/10.1351/goldbook.M04017).
5) monomer molecule (http://doi.org/10.1351/goldbook.M04019).
6) oligomer molecule (http://doi.org/10.1351/goldbook.O04286).

Source: PAC, 2007, 79, 1801. 'Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007)' on page 1805 (https://doi.org/10.1351/pac200779101801)

Citation: 'functionality, \(f\)' 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.FT07505

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