When an alcohol is mixed with this substance, its 
When an alcohol is mixed with this substance, its hydroxyl proton signal disappears from its NMR due to chemical exchange; unlike a related substance, this compound does not have an NMR signal. The Sudbury Neutrino Observatory attempted to detect neutrinos from the Sun interacting with this substance. In Operation Gunnerside during World War II, the Allies destroyed a production facility of this compound in Oslo. Because CANDU nuclear reactors use this substance as a coolant and as a source of neutrons, they do not require enriched uranium. Harold Urey first synthesized this compound. Its atomic mass is 20 daltons, due to two extra neutrons. For 10 points, name this compound known as deuterium oxide.
When an alcohol is mixed with this substance, its hydroxyl proton signal disappears from its NMR due to chemical exchange; unlike a related substance, this compound does not have an NMR signal.
heavy water [or deuterium oxide until it is read]