For general access to the Wolfram Knowledgebase, use entities of type Isotope instead of IsotopeData.


gives the value of the specified property for the isotope with atomic number Z and mass number A.


gives the value of the property for the named isotope.


  • Isotope names can be specified by the corresponding element name or abbreviation, followed by a mass number A (e.g. "Sodium23" or "Na23"). The form {"name",A} can also be used.
  • IsotopeData[] gives a list of all known isotopes.
  • IsotopeData[{Z,A}] gives the isotope name.
  • IsotopeData["name"] or IsotopeData[Z] gives a list of all known isotopes of the element with the specified name or atomic number.
  • IsotopeData[{Z,A}] gives Missing["Unknown"] when no isotope with the specified Z, A is known.
  • IsotopeData["Properties"] gives a list of all properties available for the isotopes.
  • Properties that do not apply or are not known in a particular case are indicated by Missing[].
  • Numerical values that are known only to a certain precision are typically tagged with their precision, and given in arbitrary-precision form.
  • Basic isotope properties include:
  • "AtomicMass"mass of isotope in atomic mass units
    "AtomicNumber"atomic number
    "BindingEnergy"binding energy
    "IsotopeAbundance"relative isotope abundance
    "MassExcess"mass excess
    "MassNumber"mass number
    "NeutronNumber"number of neutrons
    "QuantumStatistics" for bosons, for fermions
  • Quantum number and structural properties include:
  • "MagneticMoment"magnetic moment in nuclear magnetons
    "QuadrupoleMoment"electric quadrupole moment in barns
  • Decay-related properties include:
  • "BranchingRatios"branching ratio of each decay mode
    "DaughterNuclides"final daughter nuclide of each mode
    "DecayEnergies"decay energy of each mode in keV
    "DecayModes"list of observed decay modes
    "DecayModeSymbols"standard symbols for observed decay modes
    "DecayProducts"list of all final decay products and branching ratios
    "HalfLife"decay half-life in seconds
    "Lifetime"decay lifetime in seconds
    "MolarRadioactivity"radioactivity per mole
    "SpecificRadioactivity"specific radioactivity
    "Stable"whether the isotope is stable
    "Width"decay width in MeV
  • Examples of decay mode designations include: "AlphaDecay", "BetaDecay", "BetaPlusDecay", "ProtonEmission", "NeutronEmission", "SpontaneousFission", and "ElectronCapture". "Delayed" decay mode designations indicate the presence of an intermediate excited state.
  • Ordinary decay-related properties include only final ground-state decay products.
  • Properties of excited states include:
  • "ExcitedStateEnergies"list of energies in keV
    "ExcitedStateHalfLives"list of decay half-lives in seconds
    "ExcitedStateLifetimes"list of decay lifetimes in seconds
    "ExcitedStateParities"list of parities
    "ExcitedStateSpins"list of spins
    "ExcitedStateWidths"list of decay widths in MeV
  • Names-related properties include:
  • "FullSymbol"full abbreviation
    "Name"English name (e.g. "helium 4")
    "StandardName"standard Wolfram Language name (e.g. "Hydrogen3")
    "Symbol"standard abbreviation
  • IsotopeData["class"] gives a list of isotopes in the specified class. IsotopeData[name,"class"] gives True or False depending on whether the element corresponding to name is in the specified class.
  • Classes of isotopes include:
  • "AlphaDecay"decays via decay
    "BetaDecay"decays via decay
    "BetaPlusDecay"decays via decay
    "Boson"obeys BoseEinstein quantum statistics
    "ElectronCapture"decays via electron capture
    "Fermion"obeys FermiDirac quantum statistics
    "NeutronEmission"decays via neutron emission
    "ProtonEmission"decays via proton emission
    "SpontaneousFission"decays via spontaneous fission
    "Stable"stable with respect to radioactive decay
    "Unstable"unstable with respect to radioactive decay
  • IsotopeData["name","property","ann"] gives various annotations associated with a property. Typical annotations include:
  • "Description"short textual description of the property
    "Interval"uncertainty range given by Interval[]
    "LongDescription"longer textual description of the property
    "Note"additional information about the property
    "Units"units in which the value is given
    "UnitsName"English name for the units used
    "UnitsNotation"notation for the units used
    "UnitsStandardName"Wolfram Language standard name for the units used
    "Value"property value (default if no annotation is specified)


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Basic Examples  (4)

Find the atomic mass of uranium-235:

Find the magnetic moment of tritium:

Find the decay modes of lead-181:

Plot the excited state energies of oxygen-15:

Scope  (17)

Names and Classes  (8)

Obtain a list of all the isotopes sorted by atomic number and mass number:

Get a list of known isotopes for an element:

An isotope can be specified in several specific ways:

Find the English name of an isotope:

Get the standard symbol for an isotope:

Including atomic number and neutron number:

Find the list of isotope classes:

Find the list of isotopes belonging to a class:

Test whether an isotope belongs to a class:

Properties and Annotations  (5)

Get a list of properties for a particular isotope:

Get a short textual description of a property:

Get a longer textual description:

Find the units in which a property value is given:

Get units in proper textual form:

Get units as notation:

Uncertainty is represented using Interval:

Find additional notes about properties:

Property Values  (4)

A property value can be any valid Wolfram Language expression:

Values are listed in the same order for all excited state and decay properties:

Get properties for the second decay mode:

Use Precision to find out the number of significant digits for a property:

A property that is unknown for an isotope has the value Missing["Unknown"]:

A list of possible values due to uncertainty:

Generalizations & Extensions  (1)

Use a string expression to find isotopes with the same mass number:

Applications  (5)

Find the distribution of lifetimes:

Make an isotope chart of lifetimes:

Make an isotope chart of binding energies:

Draw a decay network:

Plot magnetic moment against spin:

Quadrupole moment versus spin:

Properties & Relations  (8)

Use Table to obtain the property values for a list of isotopes:

The same thing using Map:

Get values of multiple properties for a list of isotopes:

Display the data as a formatted table using Grid and Text:

Use DeleteCases to filter out non-missing data:

Alternatively use Cases with Except to filter out missing data:

Use ListPlot to plot a list of property values:

Missing data is automatically excluded in plotting functions:

Use ListLogPlot when the data spans many orders of magnitude:

Use ParticleData to find information about the elementary particles:

Use ElementData to find physical and chemical properties of an element:

Use ChemicalData to find information about a molecule:

Possible Issues  (2)

Using non-standard isotope and property names will not work:

Use string functions to find the standardized names:

Arithmetical operations cannot be carried out on Missing entries:

Remove the Missing entries before performing operations:

Neat Examples  (1)

Use FixedPoint to find all reachable nuclides from a given starting point:

Use RelationGraph to visualize the decay chain from uranium 232:

Wolfram Research (2007), IsotopeData, Wolfram Language function, (updated 2014).


Wolfram Research (2007), IsotopeData, Wolfram Language function, (updated 2014).


Wolfram Language. 2007. "IsotopeData." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2014.


Wolfram Language. (2007). IsotopeData. Wolfram Language & System Documentation Center. Retrieved from


@misc{reference.wolfram_2023_isotopedata, author="Wolfram Research", title="{IsotopeData}", year="2014", howpublished="\url{}", note=[Accessed: 21-April-2024 ]}


@online{reference.wolfram_2023_isotopedata, organization={Wolfram Research}, title={IsotopeData}, year={2014}, url={}, note=[Accessed: 21-April-2024 ]}