## Chemistry: Molecular Approach (4th Edition)

The formula of the compound is $PBr_3$
The name of the compound is the name of the first element, phosphorus, with no prefix to indicate one atom, followed by the base name of the second element, $brom$, prefixed by $tri-$ to indicate three bromine atoms and given the suffix -ide. So, the formula of the compound is $PBr_3$.