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FindIsomers[chem]

returns a list of molecules with the same chemical formula as chem.

FindIsomers[chem,form]

finds isomers of chem and returns them in the given form.

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FindIsomers

FindIsomers[chem]

returns a list of molecules with the same chemical formula as chem.

FindIsomers[chem,form]

finds isomers of chem and returns them in the given form.

Details

  • Isomers are molecules with the same chemical formula but different structures. For example, cyclohexane and hex-2-ene both have the formula C6H12:
  • Possible forms for chem include:
  • ChemicalFormula[…]a chemical formula
    Molecule[…]a molecule
    Entity["Chemical",…]a chemical entity
    BioSequence[…]a biomolecular sequence
  • FindIsomers draws on several sources, including the Wolfram Knowledgebase and external services such as "PubChem". Only those molecules that have entries in these databases will be returned.
  • If no result is found, FindIsomers will return an empty list.
  • form should be one of the following:
  • "Molecule"a list of molecules
    "Entity"entities of the type "Chemical"
    "PubChemCompoundID"a list of ExternalIdentifier objects
    "SMILES"a list of SMILES strings

Examples

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Basic Examples  (3)

Find the isomers of pentane:

Wolfram Language code: FindIsomers[Molecule["pentane"]]

Look up their names:

Wolfram Language code: MoleculeName /@ %

Find isomers given a chemical formula:

Wolfram Language code: FindIsomers[ChemicalFormula["C3H5NO"]]//Short

Find isomers in the Wolfram Knowledgebase

Wolfram Language code: FindIsomers[Molecule[{"Cl", "C", "O", "C", "C", "C", "C"}, {Bond[{1, 2}, "Single"], Bond[{2, 3}, "Double"], Bond[{2, 4}, "Single"], Bond[{4, 5}, "Single"], Bond[{4, 6}, "Single"], Bond[{6, 7}, "Single"], Bond[{7, 4}, "Single"]}, {}], "Entity"]

Applications  (1)

Find isomers of caffeine that have an aromatic bond between oxygen and nitrogen:

Wolfram Language code: mols = Select[FindIsomers[(Entity["Chemical", "Caffeine"])], MoleculeContainsQ[Bond[{Atom["O", "AromaticAtomQ" -> True], Atom["N", "AromaticAtomQ" -> True]}]]]; Length[mols]

Take five random isomers from this list and find their maximum common substructure:

Wolfram Language code: SeedRandom[987654]; selection = RandomSample[mols, 5]; mcs = MoleculeMaximumCommonSubstructure[selection, "CompleteRings"]

View the molecules in 3D, highlighting the common substructure:

Wolfram Language code: MoleculePlot3D[#, mcs]& /@ selection

Align the molecules in 3D:

Wolfram Language code: aligned = MoleculeAlign[First@selection, selection, mcs]; Show[MoleculePlot3D[#, mcs]& /@ aligned]

Possible Issues  (1)

Some chemical formulas will not have any entry in the sources queried by FindIsomers:

Wolfram Language code: FindIsomers[ChemicalFormula["C6H22"]]
Wolfram Research (2021), FindIsomers, Wolfram Language function, https://reference.wolfram.com/language/ref/FindIsomers.html.

Text

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

CMS

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

APA

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

BibTeX

@misc{reference.wolfram_2026_findisomers, author="Wolfram Research", title="{FindIsomers}", year="2021", howpublished="\url{https://reference.wolfram.com/language/ref/FindIsomers.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_findisomers, organization={Wolfram Research}, title={FindIsomers}, year={2021}, url={https://reference.wolfram.com/language/ref/FindIsomers.html}, note=[Accessed: 12-June-2026]}