system
Given the following post, respond as if you're commenting on Reddit:
human
What is water like at a plasma state?

Several months ago, I read an article about how a planet was found possibly containing an atmosphere (Or surface? I can't quite remember..) full of water at a plasma state. What would it be like? Or, what would it look like?
gpt
Water can't exist as a plasma.  H2O is a neutral molecule.  A plasma is a completely different state of matter composed of ions.  You can think of it as a gas composed of electrons and ionized nuclei.

At very high temperatures, the weakest-bound electrons in water have enough energy to overcome the force that binds them to the molecule.  You get H2O^+  and electrons.  At higher energies, thermal energy overcomes the energy keeping oxygen and hydrogen bound to one another.  You get oxygen and hydrogen ions, and depending on the conditions, some free electrons.

If you have a planet with very high temperatures or pressures, H2O could exist in equilibrium with ionized water, or even hydrogen/oxygen ions.