13NNH3

13NNH3 is a designation encountered in some chemical and biochemical literature. It is not a single, universally defined compound. Rather, it is a notation used to indicate a nitrogen-containing molecule in which the nitrogen atom(s) include the isotope nitrogen-13 (13N). The exact connectivity and molecular formula depend on the source and the experiment being described.

One common interpretation in isotopic labeling studies is a di-nitrogen framework where an ammonia (NH3) or amine fragment is attached to a second nitrogen that bears the 13N label. For example, a molecule written as 13N–NH3 would imply a two-nitrogen species with one 13N atom, though the precise structure must be confirmed from the original publication. Such labeling is used to trace nitrogen transfer, follow reaction pathways, or enable NMR and mass-spectrometric differentiation between isotopologues.

In practice, 13NNH3 appears in contexts such as reaction mechanism studies, catalysis, or astrochemistry, where scientists track nitrogen-containing intermediates or products using nitrogen-13 labeling. The label shifts the mass and can affect NMR chemical shifts, enabling experimental discrimination from the non-labeled counterpart.

To interpret a specific instance of 13NNH3, consult the source documentation for the exact structural notation, see the accompanying figures or SMILES/InChI strings, and verify the intended connectivity and isotope placement. If necessary, contact the authors or examine the supplementary information for unambiguous details. See also isotopologues, isotopic labeling, nitrogen-13, and hydrazine-bearing compounds for related concepts.