Water that contains two hydrogen atoms instead of one is still called water, or more specifically, H₂O.

Here's why:

* The chemical formula defines the molecule: The chemical formula H₂O tells us that a water molecule consists of two hydrogen atoms (H) and one oxygen atom (O).

* Isotopes don't change the molecule: You're likely thinking about isotopes of hydrogen. There are three main isotopes of hydrogen: protium (¹H, the most common), deuterium (²H, also called heavy hydrogen), and tritium (³H). While deuterium has one proton and one neutron, protium only has a proton. However, the number of neutrons doesn't change the fundamental chemical nature of the molecule.

So, water with two hydrogen atoms is still water, regardless of whether those hydrogen atoms are protium or deuterium. Water with two deuterium atoms is called heavy water, and it has slightly different properties than regular water.