Sodium deuteroxide is primarily used in nuclear magnetic resonance (NMR) spectroscopy as a deuterated solvent modifier. It helps in the study of molecular structures by replacing exchangeable protons with deuterium, reducing signal interference in the NMR spectrum. This chemical is also employed in organic synthesis for deuterium labeling, enabling researchers to trace reaction pathways and mechanisms. Additionally, it plays a role in the preparation of deuterated compounds, which are essential in various scientific research applications, including pharmaceutical development and metabolic studies. Its use in isotopic labeling experiments further aids in understanding biological processes and chemical reactions at a molecular level.