Here's how to break down the name:

* Di-carbon: This indicates there are two carbon atoms (C₂).

* Pentoxide: This indicates there are five oxygen atoms (O₅).

Therefore, the combined chemical formula is C₂O₅.

However, it's important to note that di-carbon pentoxide (C₂O₅) does not exist as a stable compound. It is a theoretical compound that has not been synthesized or observed.