Has to be electrically neutral
Ionic Compound Formulas
Compound Name Formula Cation Anion
lithium fluoride LiF Li+ F-
sodium chloride NaCl Na+ Cl-
calcium chloride CaCl2 Ca2+ Cl-
iron(II) oxide FeO Fe2+ O2-
aluminum sulfide Al2S3 Al3+ S2-
iron(III) sulfate Fe2(SO3)3 Fe3+ SO32-