You're asking for the chemical formula of a compound formed between copper and bromine. Here's how to determine it:

* Copper (Cu) can have multiple oxidation states (charges). To know which one to use, you'll need to consider the context or be given a specific oxidation state.

* Bromine (Br) typically has an oxidation state of -1.

Possible Compounds:

* Copper(I) Bromide (CuBr): This is formed when copper has a +1 oxidation state.

* Copper(II) Bromide (CuBr₂): This is formed when copper has a +2 oxidation state.

Without additional information, you can't definitively say which formula is "correct." You need to know which oxidation state of copper is involved.