Final answer:
The formula for the compound formed between the ammonium ion and the carbonate ion is (NH4)2CO3.
Step-by-step explanation:
The formula of the compound formed between the ammonium ion (NH4+) and the carbonate ion (CO32-) is (NH4)2CO3. To determine this, we need to balance the charges between the two ions. The ammonium ion has a +1 charge while the carbonate ion has a -2 charge. In order to balance the charges, we need two ammonium ions for every carbonate ion, resulting in the formula (NH4)2CO3.