To balance the reaction, we need to identify the compound formed when barium chlorate \(\text{Ba(ClO}_3\text{)}_2\) decomposes. The balanced chemical equation for the decomposition of barium chlorate is as follows:
\[ \text{Ba(ClO}_3\text{)}_2 \rightarrow \text{BaCl}_2 + 3 \text{O}_2 \]
So, filling in the blank:
Ba(CIO3)2 > BaCl2 + 3O2