stoichiometric number, \(\nu\)

https://doi.org/10.1351/goldbook.S06025
A chemical reaction of known @S06026@ 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 @S06021@ numbers, \(\nu _{\text{Y}}\) and \(\nu _{\text{Z}}\), for Y and Z respectively. For the reactants the @S06021@ numbers are the negatives of the numbers appearing in the equation; for example the @S06021@ number \(\nu _{\text{A}}\) for the reactant A is \(-a\). In other words, the @S06021@ numbers are positive for products and negative for reactants.
Sources:
Green Book, 2nd ed., p. 42 [Terms] [Book]
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 187 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 993 [Terms] [Paper]
See also:
PAC, 1996, 68, 1167. (Pesticides report 36. Glossary of terms relating to pesticides (IUPAC Recommendations 1996)) on page 1168 [Terms] [Paper]