Term: stoichiometric number, \(\nu\)
https://doi.org/10.1351/goldbook.S06025

Definition:
A chemical reaction of known stoichiometry can be written in general as: \[a\text{A}\,+\,b\text{B}\,+\,...\rightarrow\,...\,+y\text{Y}\,+\,z\text{Z}\] For the reaction products Y and Z the numbers y and z are known as the stoichiometric numbers, ν Y and ν Z, for Y and Z respectively. For the reactants the stoichiometric numbers are the negatives of the numbers appearing in the equation; for example the stoichiometric number ν A for the reactant A is -a. In other words, the stoichiometric numbers are positive for products and negative for reactants.

Related Terms:
1) stoichiometry (http://doi.org/10.1351/goldbook.S06026).
2) stoichiometric (http://doi.org/10.1351/goldbook.S06021).

Source: Green Book, 2nd ed., p. 42 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf)

Citation: 'stoichiometric number, \(\nu\)' 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.S06025

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