Write the empirical formula for at least four ionic compounds that could be formed from the following ions:
Fe^2+, Pb^4+, NO3^-, CN^-

Answer:
Fe(NO3)2, Pb(CN)4, Fe(CN)2, Pb(NO3)4
Determine the empirical formula for the ionic compound formed from Fe^{2+} and NO_{3}^{-}
The charges must balance, so the empirical formula is Fe(NO3)2
Determine the empirical formula for the ionic compound formed from Pb^{4+} and CN^{-}
The charges must balance, so the empirical formula is Pb(CN)4
Determine the empirical formula for the ionic compound formed from Fe^{2+} and CN^{-}
The charges must balance, so the empirical formula is Fe(CN)2
Determine the empirical formula for the ionic compound formed from Pb^{4+} and NO_{3}^{-}
The charges must balance, so the empirical formula is Pb(NO3)4