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Atom["sym"]

represents an atom with atomic symbol "sym".

Atom["sym",namevalue,…]

represents an atom with atomic symbol "sym" and specified properties.

Details
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Examples  
Basic Examples  
Scope  
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Atom

Atom["sym"]

represents an atom with atomic symbol "sym".

Atom["sym",namevalue,…]

represents an atom with atomic symbol "sym" and specified properties.

Details

  • For atoms within a Molecule expression, the following properties can be specified:
  • "FormalCharge"0the formal charge of the atom
    "MassNumber"Nonethe mass number of the nucleus
    "UnpairedElectronCount"0unpaired (radical) electrons
    "DisplayName"Nonea label for the atom, can be any string
  • When the "MassNumber" property is None, the molecular weight is computed using the average atomic masses, as found in ElementData. When the number is specified, the mass is taken from IsotopeData.
  • Atom can act as a pattern for functions such as AtomList and MoleculeContainsQ, matching a single atom in a molecule. In this case additional, computed properties may be specified. Typical pattern properties and their values include:
  • "AromaticAtomQ"True|False
    "AtomChirality""R"|"S"
    "AtomicMass"Real
    "AtomicNumber"Integer
    "CIPRank"Integer
    "CoordinationNumber"Integer
    "FormalCharge"Integer
    "GasteigerPartialCharge"Real
    "GeometricStericEffectIndex"Real
    "HeavyAtomCoordinationNumber"Integer
    "HydrogenCount"Integer
    "ImplicitHydrogenCount"Integer
    "MassNumber"Integer
    "MMFFPartialCharge"Real
    "OrbitalHybridization""SP"|"SP3"…
    "OuterShellElectronCount"Integer
    "PiElectronCount"Integer
    "RingAtomQ"True|False
    "TopologicalStericEffectIndex"Real
    "UnpairedElectronCount"Integer
    "UnsaturatedAtomQ"True|False
    "Valence"Integer
  • Numeric properties may also be specified using GreaterThan, LessThan, GreaterEqualThan, LessEqualThan or Between.

Examples

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Basic Examples  (2)

Build a molecule with atoms and bonds:

Retrieve the list of atoms:

Build a molecule using atoms with defined mass numbers:

Scope  (3)

Highlight all atoms with one electron:

Highlight atoms with large partial charges:

Add a label to an atom:

Wolfram Research (2019), Atom, Wolfram Language function, https://reference.wolfram.com/language/ref/Atom.html.

Text

Wolfram Research (2019), Atom, Wolfram Language function, https://reference.wolfram.com/language/ref/Atom.html.

CMS

Wolfram Language. 2019. "Atom." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/Atom.html.

APA

Wolfram Language. (2019). Atom. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Atom.html

BibTeX

@misc{reference.wolfram_2025_atom, author="Wolfram Research", title="{Atom}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/Atom.html}", note=[Accessed: 08-August-2025]}

BibLaTeX

@online{reference.wolfram_2025_atom, organization={Wolfram Research}, title={Atom}, year={2019}, url={https://reference.wolfram.com/language/ref/Atom.html}, note=[Accessed: 08-August-2025]}