Used extensively as a solvent in nuclear magnetic resonance (NMR) spectroscopy due to its deuterium atoms, which provide a clear and distinct signal without interfering with the analysis of other hydrogen atoms in the sample. It is particularly valuable in organic chemistry research for studying molecular structures and dynamics. Additionally, it serves as a reference standard in mass spectrometry and other analytical techniques to ensure accuracy and consistency in measurements. Its stable isotopic composition also makes it useful in tracing and labeling experiments in chemical and biochemical studies.