To determine the empirical formula of the compound given, we need to determine the ratio of each element in the compound. An empirical formula is a formula that gives the proportions of the elements present in a certain compound however it does not give the actual numbers or the arrangement of the atoms.The empirical formula of the ionic compounds that could be formed from the given ions are calcium bromide (CaBr2), calcium sulfide (CaS), Lead Bromide (PbBr4) and Lead sulfide (Pb2S4).