* Rubidium (Rb) is a metal and readily loses its outermost electron to become a positively charged ion (Rb⁺).

* Carbonate (CO₃²⁻) is a polyatomic ion formed from carbon and oxygen atoms. It has a negative charge due to the sharing of electrons within the ion.

The attraction between the positively charged rubidium ions (Rb⁺) and the negatively charged carbonate ions (CO₃²⁻) forms the ionic bond. This strong electrostatic attraction holds the compound together.