Barium Carbonate-13C is an isotopically labeled inorganic salt where the carbon atom is the stable isotope carbon-13. It is a white, odorless powder with the chemical formula Ba13CO3. As a labeled compound, it is distinct from its natural abundance counterpart due to the enrichment of the 13C isotope. The primary application of Barium Carbonate-13C is as a specialized reagent in scientific research, particularly in nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The 13C label serves as a non-radioactive tracer, enabling researchers to study reaction mechanisms, metabolic pathways, and material structures by tracking the fate of the carbon atom. It is also used in the synthesis of other 13C-labeled compounds and in geochemical studies as a standard. This compound is highly toxic if ingested or inhaled, as it dissolves in stomach acid to form soluble, poisonous barium ions. It must be handled with appropriate personal protective equipment in a controlled laboratory environment. Its use is almost exclusively confined to analytical and synthetic research laboratories rather than large-scale industrial processes.