Name _________________________
Naming Ionic Compounds
Ionic compounds are generally composed of a metal and a nonmetal. Formulas for ionic
compounds are always written using the lowest whole number ratios of the cation (positive ion)
and anion (negative ion).
Ionic compounds are named by first naming the cation and then the anion. For monatomic
cations with only one possible positive charge (elements in group 1, 2, 3 and Al3+, see oxidation
numbers on the Periodic Table), simply name the element of the cation, i.e. Na+ is the sodium
ion. For monoatomic anions (nonmetals), the negative charges typically are the same as the
number of electrons required to obtain a Noble Gas electronic configuration. To name a
monoatomic anion, take the root of the elements name and add the suffix –ide, i.e. Cl- is the
chloride ion. Therefore, to name a simple binary ionic compound such as NaCl, name the cation
and then the anion ending in –ide, i.e. sodium chloride. In some cases the cation can have more
than one possible charge (usually a d-block metal). It is therefore necessary to use the so-called
“stock naming system” by indicating the charge of the cation using a Roman numeral after the
cation’s name. For example, Fe2O3 is named iron (III) oxide, whereas FeO is iron (II) oxide. In
some cases, the ionic compound will contain polyatomic ions. To name these compounds, again
simply name the cation and then the anion. Table 1 contains a list of cations and anions, along
with their names. These ions can be used to complete the following.
Table 1. Formulas and Names of various selected cations and anions.
Formula
NH4+
Li+
Na+
K+
Mg2+
Ca2+
Sr2+
Sc3+
Cr2+
Cr3+
Cr6+
Fe2+
Fe3+
Mn2+
Mn3+
Cu+
Cu2+
Pb2+
Zn2+
Al3+
Name
Ammonium ion
Lithium ion
Sodium ion
Potassium ion
Magnesium ion
Calcium ion
Strontium ion
Scandium ion
Chromium (II) ion
Chromium (III) ion
Chromium (VI) ion
Iron (II) ion
Iron (III) ion
Manganese (II) ion
Manganese (III) ion
Copper (I) ion
Copper (II) ion
Lead (II) ion
Zinc ion
Aluminium ion
© Van Der Sluys, 2004
Formula
FClBrIO2S2N3C4NO3NO2CO32SO42SO32PO43PO33ClOClO2ClO3ClO4OH-
Name
Fluoride ion
Chloride ion
Bromide ion
Iodide ion
Oxide ion
Sulfide ion
Nitride ion
Carbide ion
Nitrate ion
Nitrite ion
Carbonate ion
Sulfate ion
Sulfite ion
Phosphate ion
Phosphite ion
Hypochlorite ion
Chlorite ion
Chlorate ion
Perchlorate ion
Hydroxide ion
Name _________________________
Naming Ionic Compounds
Fill in the blank spaces of the following table.
Formula
Cation
Anion
Ca2+
CO32-
Name of ionic
compound
KCl
Iron (II) sulfate
Fe2(SO4)3
Mg2+
ClChromium (III)
Chloride
Zn3(PO4)2
Al3+
OHammonium nitrate
(NH4)2SO4
Na+
FCopper (II) sulfate
Ca(NO3)2
Zn2+
© Van Der Sluys, 2004
N3-
Name _________________________
Naming Ionic Compounds
Answers
Formula
Cation
Anion
Name of ionic
compound
KCl
K+
Cl-
Potassium chloride
CaCO3
Ca2+
CO32-
Calcium carbonate
FeSO4
Fe2+
SO42-
Iron (II) sulfate
Fe2(SO4)3
Fe3+
SO42-
Iron (III) sulfate
MgCl2
Mg2+
Cl-
Magnesium
chloride
CrCl3
Cr3+
Cl-
Chromium (III)
Chloride
Zn3(PO4)2
Zn2+
PO43-
Zinc phosphate
Al(OH)3
Al3+
OH-
Aluminum
hydroxide
NH4NO3
NH4+
NO3-
ammonium nitrate
(NH4)2SO4
NH4+
SO42-
Ammonium sulfate
NaF
Na+
F-
Sodium fluoride
CuSO4
Cu2+
SO42-
Copper (II) sulfate
Ca(NO3)2
Ca2+
NO3-
Calcium nitrate
Zn3N2
Zn2+
N3-
Zinc nitride
© Van Der Sluys, 2004
Name _________________________
© Van Der Sluys, 2004
Naming Ionic Compounds