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ReactionBalance[rxn]

returns a version of the reaction rxn in which the stoichiometric coefficients for elements in the reactants and products are balanced.

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ReactionBalance

ReactionBalance[rxn]

returns a version of the reaction rxn in which the stoichiometric coefficients for elements in the reactants and products are balanced.

Details

  • rxn should be a ChemicalReaction object or a string that can be converted into a reaction.
  • If the reaction cannot be balanced, a Failure object is returned.

Examples

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Basic Examples  (3)

Balance a chemical reaction:

Wolfram Language code: ReactionBalance[ChemicalReaction[Association[ChemicalFormula[{"C" -> 8, "H" -> 10, "N" -> 4, "O" -> 2}] -> 1, ChemicalFormula[{"O" -> 2}] -> 1] -> Association[ChemicalFormula[{"C" -> 7, "H" -> 8, "N" -> 4, "O" -> 2}] -> 1, ChemicalFormula[{"H" -> 2, "O" -> 1}] -> 1, ChemicalFormula[{"C" -> 1, "O" -> 2}] -> 1]]]

Balance a reaction entered as a string:

Wolfram Language code: ReactionBalance["FeCl2 + Na3PO4 -> Fe3(PO4)2 + NaCl"]

Balance a reaction with charged species:

Wolfram Language code: ReactionBalance[ChemicalReaction[ Association[ChemicalFormula[{"Cu" -> 1}, Association["Phase" -> "Aqueous", "NetCharge" -> 1]] -> 1, ChemicalFormula[{"Fe" -> 1}, Association["Phase" -> "Solid"]] -> 1] -> Association[ChemicalFormula[{"Fe" -> 1}, Association["Phase" -> "Aqueous", "NetCharge" -> 3]] -> 1, ChemicalFormula[{"Cu" -> 1}, Association["Phase" -> "Solid"]] -> 1]]]

Scope  (1)

Reactions are not balanceable if some elements are missing:

Wolfram Language code: ReactionBalance[ChemicalReaction[Association[ChemicalFormula[{"Fe" -> 1, "Cl" -> 2}] -> 1, ChemicalFormula[{"Na" -> 3, "P" -> 1, "O" -> 4}] -> 1] -> Association[ChemicalFormula[{"Fe" -> 3, {"P" -> 1, "O" -> 4} -> 2}] -> 1, ChemicalFormula[{"K" -> 1, "Cl" -> 1}] -> 1]]]

Applications  (1)

Write a function to return balanced combustion reactions:

Wolfram Language code: combustionReaction[mol_ ? (MoleculeFreeQ[Atom[Except["C" | "H" | "O"]]])] := ReactionBalance[ChemicalReaction[{mol, Entity["Chemical", "MolecularOxygen"]} -> {Entity["Chemical", "CarbonDioxide"], Entity["Chemical", "Water"]}]]

Find the balanced reactions to combust several hydrocarbons:

Wolfram Language code: combustionReaction /@ {"benzene", "cyclohexane", "anthracene"}

Possible Issues  (1)

If a reaction cannot be balanced uniquely, the balancing with the lowest sum of stoichiometric coefficients is returned:

Wolfram Language code: ReactionBalance[ChemicalReaction[Association[ChemicalFormula[{"C" -> 1, "O" -> 1}] -> 1, ChemicalFormula[{"C" -> 1, "O" -> 2}] -> 1, ChemicalFormula[{"H" -> 2}] -> 1] -> Association[ChemicalFormula[{"C" -> 1, "H" -> 4}] -> 1, ChemicalFormula[{"H" -> 2, "O" -> 1}] -> 1]]]

A different balancing of the same reaction:

Wolfram Language code: ReactionBalancedQ[ChemicalReaction[Association[ChemicalFormula[{"C" -> 1, "O" -> 1}] -> 1, ChemicalFormula[{"C" -> 1, "O" -> 2}] -> 2, ChemicalFormula[{"H" -> 2}] -> 11] -> Association[ChemicalFormula[{"C" -> 1, "H" -> 4}] -> 3, ChemicalFormula[{"H" -> 2, "O" -> 1}] -> 5]]]

Neat Examples  (1)

Balance a complicated redox reaction:

Wolfram Language code: ReactionBalance[ChemicalReaction[ Association[ChemicalFormula[{{"Cr" -> 1, {"N" -> 2, "H" -> 4, "C" -> 1, "O" -> 1} -> 6} -> 4, {"Cr" -> 1, {"C" -> 1, "N" -> 1} -> 6} -> 3}] -> 1, ChemicalFormula[{"K" -> 1, "Mn" -> 1, "O" -> 4}] -> 1, ChemicalFormu ... Mn" -> 1, "S" -> 1, "O" -> 4}] -> 1, ChemicalFormula[{"C" -> 1, "O" -> 2}] -> 1, ChemicalFormula[{"K" -> 1, "N" -> 1, "O" -> 3}] -> 1, ChemicalFormula[{"K" -> 2, "S" -> 1, "O" -> 4}] -> 1, ChemicalFormula[{"H" -> 2, "O" -> 1}] -> 1]]]
Wolfram Research (2021), ReactionBalance, Wolfram Language function, https://reference.wolfram.com/language/ref/ReactionBalance.html.

Text

Wolfram Research (2021), ReactionBalance, Wolfram Language function, https://reference.wolfram.com/language/ref/ReactionBalance.html.

CMS

Wolfram Language. 2021. "ReactionBalance." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/ReactionBalance.html.

APA

Wolfram Language. (2021). ReactionBalance. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/ReactionBalance.html

BibTeX

@misc{reference.wolfram_2026_reactionbalance, author="Wolfram Research", title="{ReactionBalance}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/ReactionBalance.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_reactionbalance, organization={Wolfram Research}, title={ReactionBalance}, year={2021}, url={https://reference.wolfram.com/language/ref/ReactionBalance.html}, note=[Accessed: 12-June-2026]}