# How do you write the formula of vanadium (IV) carbonate?

Since it is specified as vanadium(IV), we know that we are using the $+ 4$ cation, $\setminus m a t h b f \left({\text{V}}^{4 +}\right)$, as the roman numerals correspond to the cationic charge.
Also, carbonate is the $\setminus m a t h b f \left({\text{CO}}_{3}^{2 -}\right)$ polyatomic ion.
Therefore, we are looking at ${\text{V}}^{4 +}$ and ${\text{CO}}_{3}^{2 -}$ in constructing this molecular formula, and we would get:
color(blue)("V"("CO"_3)_2)