Formic acid-d2, a deuterated form of formic acid, is primarily used in research and analytical applications. It serves as a solvent and reagent in nuclear magnetic resonance (NMR) spectroscopy, where its deuterium atoms provide a clear signal without interfering with the analysis of other hydrogen atoms in the sample. This makes it valuable for studying molecular structures and dynamics in organic and biochemical compounds. Additionally, it is employed in kinetic studies and isotopic labeling experiments to trace reaction mechanisms and pathways. Its use in specialized chemical synthesis and as a reference standard in mass spectrometry further highlights its importance in advanced scientific investigations.