Deuterated water, also known as heavy water, is a form of water where the hydrogen atoms are replaced with deuterium, a heavier isotope of hydrogen. This gives deuterated water a different chemical structure, represented as D₂O instead of the common H₂O. It is used in various scientific applications, including nuclear reactors and NMR spectroscopy. In biological research, deuterated water can help trace metabolic processes without interfering with normal biological functions. While it is generally safe in small amounts, high concentrations can be toxic to living organisms. Thus, its use is carefully controlled in laboratory settings.