Deuterium, H2, is a stable isotope of Hydrogen meaning it does not have radioactive decay. Deuterium’s nucleus, a deuteron, consists of one proton and one neutron. Deuterium also has a higher boiling, melting, critical pressure, and critical temperature compared to a regular Hydrogen atom. In about 6420 hydrogen there is one deuterium, making it rare.

Because of its rarity, many scientists have had an interest in it. Deuterium could be found in the ocean naturally in a substance called “heavy water”, which is about 10.6% denser than regular water. However, nearly all of it was created in the “Big Bang” 13.8 billion years ago and it was found in such small amounts in our oceans (about 1 part in 4500). 

Even though it's hard to find, there are many uses of it. This includes its usage in nuclear power, agriculture, live vaccines, and many more. For example, nuclear power uses the unique property of how it absorbs less neutrons than hydrogen. This is useful due to the fact that nuclear fission uses neutrons to react with each other to generate electricity.