The ionic equation for the reaction between FeCl2(aq) and Na2CO3(aq) to form FeCO3(s) and 2NaCl(aq) is:

Fe²⁺(aq) + CO3²⁻(aq) → FeCO3(s)

The spectator ions, Na⁺ and Cl⁻, are omitted from the ionic equation because they do not participate in the reaction.