# What is the formula for barium bromide?

$B a B {r}_{2}$...............
Barium is an $\text{alkaline-earth metal}$............i.e. $\text{Group 2}$.
And thus barium commonly forms a $B {a}^{2 +}$ ion, just as the halogen bromine, commonly forms a $B {r}^{-}$. And hence the salt formed is $B a B {r}_{2}$.