The chemical formula for copper(I) dichromate is Cu₂Cr₂O₇. Here's how to break it down:

* Copper(I): This indicates that copper has a +1 charge (Cu⁺).

* Dichromate: This is a polyatomic ion with the formula Cr₂O₇²⁻, carrying a -2 charge.

To balance the charges, you need two copper ions (2 x +1 = +2) to neutralize the -2 charge of the dichromate ion.