sentences: a water molecure is made of 2 hydrogen atoms and 1 oxygen atom
docs: uranium is element. water_of_crystallization is water. sodium_hydroxide is crystal. water is compound_of_hydrogen_and_oxygen. undine is water_sprite. helium is chemical_element. water has oxygen_and_hydrogen chemical_formula_for_water is h2o. atoms_in_water is hydrogen_and_oxygen. one_molecule_of_water has three_atoms