N14

Nitrogen-14, often written as 14N, is the most abundant stable isotope of nitrogen. It has a mass number of 14, corresponding to seven protons and seven neutrons in the nucleus. In nature it accounts for about 99.63% of all nitrogen atoms.

Nuclear properties of 14N include a nuclear spin of I = 1 and a quadrupole moment. These characteristics influence its behavior in nuclear magnetic resonance (NMR) experiments, where 14N signals are typically broad and less sensitive than those from spin-1/2 nuclei. As a result, 14N NMR is less commonly used for structural studies, and researchers more often rely on the 15N isotope for high-resolution NMR analyses.

Natural abundance and occurrence: 14N is ubiquitous in Earth's atmosphere as the dominant component of molecular nitrogen (N2). A small fraction, about 0.37%, is the heavier isotope 15N. 14N is also present in all nitrogen-containing biomolecules, including amino acids and nucleotides, making it a fundamental part of biological systems.

Applications and role: In biology and chemistry, 14N is a core element of many molecules. While its direct use in high-resolution spectroscopy is limited by its quadrupolar nature, 14N is routinely involved in isotopic labeling, tracer studies, and mass spectrometry analyses to determine nitrogen content and transformations. In contrast, 15N labeling is more widely used for detailed structural and metabolic investigations due to its favorable NMR properties.

Notable alternative uses: The isotope is sometimes referenced in broader discussions of nitrogen chemistry and isotopic composition in environmental and geological contexts, as part of tracing nitrogen flows and cycles.