AllChemicals — The Online Chemical Glossary | https://allchemicals.info/chemical/602-natural-abundance
Expert Written
|
Fact Checked
|
Sources Cited
|
AllChemicals Editorial Team
Quick Reference
Also Known As
Isotope natural abundance, relative isotope abundance, atom percent
What is Natural Abundance?
The percentage of a particular isotope found naturally on Earth relative to the total amount of that element. For example, carbon-12 has a natural abundance of about 98.9% and carbon-13 about 1.1%. Natural abundances determine the atomic weight of elements.
Properties & Characteristics
Natural abundance refers to the percentage of each isotope of an element as found in naturally occurring samples. It is expressed as atom percent (or mole fraction). For example: ¹²C = 98.93%, ¹³C = 1.07%; ¹H = 99.985%, ²H = 0.015%; ²³⁸U = 99.27%, ²³⁵U = 0.72%. Natural abundances are nearly constant on Earth but vary slightly between geological sources. They are used to calculate average atomic masses in the periodic table.
Uses & Applications
Natural abundance values are used in: calculating average atomic masses (standard atomic weights), designing NMR experiments (¹H NMR exploits 99.985% natural abundance; ¹³C NMR sensitivity is low at 1.07%), isotope ratio mass spectrometry (IRMS), nuclear fuel enrichment calculations (increasing ²³⁵U above its 0.72% natural level), and in isotope geology.
Safety Information
No direct safety concern for the concept. Knowledge of natural abundance guides assessment of radiation exposure from natural radioactive isotopes: ⁴⁰K (natural abundance 0.0117%) is present in all foods and the human body, contributing to natural background radiation.
Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.
SynonymsIsotope natural abundance, relative isotope abundance, atom percent
Frequently Asked Questions
The percentage of a particular isotope found naturally on Earth relative to the total amount of that element. For example, carbon-12 has a natural abundance of about 98.9% and carbon-13 about 1.1%. Natural abundances determine the atomic weight of elements.
Natural abundance values are used in: calculating average atomic masses (standard atomic weights), designing NMR experiments (¹H NMR exploits 99.985% natural abundance; ¹³C NMR sensitivity is low at 1.07%), isotope ratio mass spectrometry (IRMS), nuclear fuel enrichment calculations (increasing ²³⁵U…
No direct safety concern for the concept. Knowledge of natural abundance guides assessment of radiation exposure from natural radioactive isotopes: ⁴⁰K (natural abundance 0.0117%) is present in all foods and the human body, contributing to natural background radiation.
Editorial standards: Chemical data is sourced from peer-reviewed literature,
CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA,
and IAEA. For educational purposes only — always consult official SDS documentation and qualified
professionals before handling chemicals.
