14N14N

14N14N, also called dinitrogen-14, is the diatomic molecule formed from two nitrogen-14 nuclei. It is the dominant isotopologue of molecular nitrogen, reflecting that natural nitrogen is predominantly 14N (about 99.63%). Consequently, the vast majority of N2 in Earth's atmosphere is 14N14N (approximately 99% of N2 molecules), with small fractions of 14N15N and trace amounts of 15N15N arising from the presence of 15N (about 0.37%).

Chemically, N2 features a triple bond between the two nitrogen atoms, giving it a bond order of 3. The bond length in the ground state is about 1.097 Å, and the dissociation energy is around 9.8 eV (approximately 941 kJ/mol). The electronic ground state is X1Σg+. Because N2 is homonuclear and has zero permanent dipole moment, its infrared transitions are forbidden; its vibrational mode is Raman-active, with a fundamental band near 2350 cm^-1.

Isotopologues of nitrogen influence vibrational and rotational spectra. For 14N14N, rotational levels and their populations are shaped by nuclear spin statistics, since 14N nuclei have spin I = 1. The molecule is a central component of Earth's atmosphere and is also abundant in interstellar and planetary environments, where it serves as a reference for isotopic studies and as an inert background in spectroscopic analyses.

Applications include atmospheric chemistry, planetary science, and isotope-rratio measurements via mass spectrometry and spectroscopy. N2, especially its most common isotopologue 14N14N, remains a fundamental reference in studies of molecular structure and dynamics.