* Metal Oxides: Rb₂O is a metal oxide, formed from the alkali metal rubidium (Rb).

* Reaction with Water: Alkali metal oxides react vigorously with water to form hydroxides, which are strong bases.

* Rb₂O + H₂O → 2RbOH

* pH: The hydroxide ions (OH-) released in this reaction increase the pH of the solution, indicating a basic nature.

Therefore, Rb₂O is classified as a basic oxide.