Nomenclature of Ionic Compounds (ANSWER KEY)
Binary Ionic Compounds:
Writing Names
1. Write the name of the cation (metal)
2. Write the name of the anion (non-metal), drop
the last syllable of the name, and change the
suffix to “-ide”.
1.
2.
3.
(Note: for the anions of O, N, H, P, Se, and Te drop the
last two syllables)
4.
Writing Formula
Examine the name of the compound. Identify the
ions and their oxidation states.
Determine the number of each ion needed to
balance the charges.
Note the ratio of positive to negative ions, and
write the formula.
Write the chemical formula, using subscripts if
needed.
(Note: for ionic compounds reduce the subscripts
whenever possible.)
Complete the following table for binary ionic compounds.
Chemical Name
Chemical Formula
Chemical Name
Chemical Formula
sodium fluoride
NaF
beryllium fluoride
BeF2
lithium chloride
LiCl
sodium iodide
NaI
beryllium bromide
BeBr2
magnesium oxide
MgO
magnesium oxide
MgO
**Omitted**
H2O
BI3
lithium sulfide
Li2S
aluminum sulfide
Al2S3
**Omitted**
BCl3
potassium oxide
K2O
aluminum oxide
Al2O3
calcium fluoride
CaF2
potassium sulfide
K2S
barium nitride
Ba3N2
silver chloride
AgCl
cesium sulfide
Cs2S
calcium chloride
CaCl2
strontium oxide
SrO
**Omitted**
BN
francium bromide
FrBr
cesium iodide
CsI
boron iodide
Binary Ionic Compounds with Multivalent Cations:
Recall that multivalent elements have multiple oxidation states (charges). When writing the names for compounds
containing multivalent cations we must indicate the oxidation state of the cation.
There are two methods for naming binary ionic compounds with multivalent cations.
1. The classical system (also referred to as the ous-ic method)
2. The IUPAC system (also referred to as the roman numeral method)
The Classical System:
1. Use the Latin name of the cation in the chemical formula. Usually, the Latin name for Hg and Sb are not used. If
the cation does not have a latin name, use the English name instead.
2. Remove the last syllable and add the suffix “-ous” or “-ic” in its place.
a. The suffix “-ous” indicates the lower oxidation state was used for the cation.
b. The suffix “-ic” indicates the higher oxidation state was used for the cation.
(Note: arsenic’s name remains unchanged when the higher oxidation state is used.)
3. Write the name of the anion and change the ending to “-ide” as you have done previously.
Classical and IUPAC Names of Common Multivalent Metal Ions
Metal
Ion
Classical Name
Fe2+
ferrous
iron
Fe3+
ferric
Cu+
cuprous
copper
2+
Cu
cupric
Sn2+
stannous
tin
Sn4+
stannic
2+
Pb
plumbous
lead
Pb4+
plumbic
3+
Sb
stibnous
antimony
Sb5+
stibnic
2+
Co
cobaltous
cobalt
Co3+
cobaltic
Au+
aurous
gold
2+
Au
auric
Hg+
mercurous
mercury
2+
Hg
mercuric
IUPAC Name
iron(II)
iron(III)
copper(I)
copper(II)
tin(II)
tin(IV)
lead(II)
lead(IV)
antimony(III)
antimony(V)
cobalt(II)
cobalt(III)
gold(I)
gold(II)
mercury(I)
mercury(II)
Complete the following table for binary ionic compounds containing multivalent cations using the classical system.
Chemical Name
Chemical Formula
Chemical Name
auric iodide
AuI2
cupric sulfide
Chemical Formula
CuS
aurous sulfide
Au2S
cuprous sulfide
Cu2S
antimonic oxide
Sb2O5
mercurous bromide
HgBr
antimonous chloride
SbCl3
ferric oxide
Fe2O3
mercuric oxide
HgO
ferrous oxide
FeO
mercurous fluoride
HgF
stannous fluoride
SnF2
plumbous arsenide
Pb3As2
stannic fluoride
SnF4
plumbic nitride
Pb3N4
**Omitted**
MnBr7
stannic oxide
SnO2
**Omitted**
MnO
stannous fluoride
SnF2
plumbous chloride
PbCl2
ferric sulfide
Fe2S3
plumbic chloride
PbCl4
ferrous hydride
FeH2
antimonic sulfide
Sb2S5
nickelic oxide
Ni2O3
antimonous arsenide
SbAs
nickelous sulfide
NiS
**Omitted**
AsI3
cuprous carbide
Cu4C
nickelous oxide
NiO
cupric oxide
CuO
cobaltous nitride
CoN
manganous phosphide
**Omitted**
ferrous fluoride
FeF2
manganic chloride
**Omitted**
mercurous fluoride
HgF2
Hg3As
cupric chloride
CuCl2
cobaltic iodide
CoI3
stannic arsenide
Sn3As4
arsenous oxide
**Omitted**
nickelic phosphide
NiP
Sb3N5
nickelous sulfide
NiS
arsenic oxide
**Omitted**
ferrous sulfide
FeS
antimonic nitride
Sb3N5 (repeat)
plumbic carbide
PbC
arsenic nitride
**Omitted**
mercurous oxide
Hg2O
cobaltous sulfide
CoS
cupric sulfide
CuS
plumbic oxide
PbO2
cuprous sulfide
Cu2S
mercurous arsenide
antimonic nitride
The IUPAC System:
1. Write the English name of the multivalent metal cation first.
2. A Roman numeral indicating the positive charge on the cation is written in brackets after the cations name. NO
SPACE is left between the cation name and the Roman numeral in brackets.
3. Write the name of the anion and change the ending to “-ide” as you have done previously.
Complete the following table for binary ionic compounds containing multivalent cations using the IUPAC system.
Chemical Name
Chemical Formula
Chemical Name
Chemical Formula
phosphorous(III) sulfide
P2S3
copper(I) bromide
CuBr
phosphorus(V) oxide
P2O5
copper(I) oxide
Cu2O
antimony(V) chloride
SbCl5
mercury(I) chloride
HgCl
antimony(III) oxide
Sb2O3
iron(III) oxide
Fe2O3
mercury(II) fluoride
HgF2
iron(II) sulfide
FeS
mercury(I) arsenide
Hg3As
tin(II) bromide
SnBr2
lead(II) nitride
Pb3N2
tin(IV) fluoride
SnF4
lead(IV) oxide
PbO2
manganese(IV) oxide
MnO2
tin(II) fluoride
SnF2
manganese(II) fluoride
MnF2
tin(IV) sulfide
SnS2
lead(II) iodide
PbI2
iron(III) hydride
FeH3
lead(IV) chloride
PbCl4
iron(II) oxide
FeO
antimony(V) oxide
Sb2O5
nickel(III) sulfide
Ni2S3
antimony(III) arsenide
SbAs
nickel(II) carbide
Ni2C
**Omitted**
AsF5
copper(I) oxide
Cu2O
**Omitted**
N2O5
copper(II) phosphide
Cu3P2
cobalt(III) arsenide
CoAs
manganese(II) chloride
MnCl2
**Omitted**
PBr5
manganese(VII) arsenide
Mn3As7
**Omitted**
PF3
carbon(II) iodide
**Omitted**
**Omitted**
SF4
carbon(IV) oxide
**Omitted**
**Omitted**
SAs2
arsenic(III) nitride
**Omitted**
nickel(III) phosphide
NiP
sulfur(IV) chloride
**Omitted**
nickel(II) oxide
NiO
arsenic(V) sulfide
**Omitted**
iron(II) sulfide
FeS
CoO
lead(IV) carbide
PbC
**Omitted**
mercury(I) sulfide
Hg2S
cobalt(II) oxide
sulfur(VI) phosphide
Ionic Compounds Containing Polyatomic Ions:
Recall that polyatomic ions are groups of atoms that act as a single ion.
Ionic compounds containing polyatomic ions are still comprised of a cation and an anion. However, the cation, or anion,
may be a polyatomic ion.
Fortunately there is only 1 polyatomic cation which we must remember – ammonium (NH4+)
All other polyatomic ions have negative charges (are anions).
Oxyanions:



Polyatomic ions containing oxygen are called oxyanions.
The number of oxygen atoms in an oxyanion can change without affecting the overall charge of the ion.
Oxyanions follow a specific naming structure related to the number of oxygen atoms.
The most stable and most common form of an oxyanion is given the suffix “-ate”.
Oxyanions containing one or more oxygen atom than the “–ate” form of the ion are given the prefix “per-“ and the
suffix “-ate”.
Oxyanions containing one less oxygen atom than the “-ate” form of the ion use the suffix “-ite”.
Oxyanions containing one less oxygen atom than the “-ite” form of the ion are given the prefix “hypo-“and the suffix “ite”.
For Example:




ClOClO2ClO3ClO4-
hypochlorite
chlorite
chlorate
perchlorate
-
has 1 less oxygen atom than the “-ite” form
has 1 less oxygen atom than the “-ate” form.
the most common and stable form of this oxyanion.
has 1 more oxygen atom than the “-ate” form
If you can remember the “-ate” form of the oxyanion you can use this relationship to determine the other chemical
formula.
In addition to oxyanions, there are a variety of polyatomic ions derived from acids and others which are considered
miscellaneous. We will discuss the polyatomic ions derived from acids during our lesson on Acid/Base Nomenclature.
Miscellaneous polyatomic ions can be looked up in your table of polyatomic ions.
Steps for Naming Ionic Compounds Containing Polyatomic Ions:
1. Write the name of the cation. If it is a metal write the name. For multivalent elements be sure to include the
charge. If it is ammonium just write ammonium.
2. Write the name of the polyatomic anion.
Complete the following table of ionic compounds containing polyatomic ions using the IUPAC system.
Chemical Name
iron(II) sulfite
Chemical Formula
Chemical Name
FeSO3
sodium sulfate
Chemical Formula
Na2SO4
nickel(III) carbonate
Ni2(CO3)3
iron(II) hypophosphite
Fe3(PO2)2
mercury(I) phosphite
Hg3PO3
potassium chlorite
KClO2
calcium perchlorate
Ca(ClO4)2
silver hypobromite
AgBrO
radium nitrite
Ra(NO2)2
sodium hypochlorite
NaClO
CoSO4
zinc carbonate
ZnCO3
manganese(IV) periodate
Mn(IO4)4
barium nitrite
Ba(NO2)2
iron(II) hyponitrite
Fe(NO)2
lithium sulfite
Li2SO3
lithium bromate
LiBrO3
magnesium perphosphate
Mg3(PO5)2
cesium iodite
CsIO2
lead(II) carbonate
PbCO3
magnesium percarbonate
MgCO4
calcium chlorate
Ca(ClO3)2
barium hypophosphite
BaPO2
iron(III) phosphate
FePO4
manganese(II) nitrite
Mn(NO2)2
tin(IV) sulfate
Sn(SO4)2
tin(IV) sulfite
Sn(SO3)2
aluminum hypophosphite
AlPO2
magnesium periodate
Mg(IO4)2
lead(II) iodate
Pb(IO3)2
aluminum hyposulfite
Al2(SO2)3
copper(I) phosphite
Cu3PO3
lead(IV) perphosphate
Pb3(PO5)4
mercury(II) sulfate
HgSO4
tin(IV) sulfate
Sn(SO4)2
antimony(V) sulfate
Sb2(SO4)5
antimony(III) hyponitrite
Sb(NO)3
calcium carbonate
CaCO3
copper(II) chlorate
Cu(ClO3)2
iron(II) carbonite
FeCO2
cobalt(II) sulfate
aluminum phosphite
AlPO3
cesium perphosphate
Cs3PO5
antimony(III) persulfate
Sb2(SO5)3
cobalt(II) hyposulfite
CoSO2
barium hyponitrite
Ba(NO)2
copper(I) pernitrate
CuNO4
beryllium carbonate
BeCO3
iron(II) chlorite
Fe(CIO2)2
Ca(ClO2)2
zinc iodate
Zn(IO3)2
calcium chlorite
Hydrates of Ionic Compounds:
Many ionic compounds form crystal structures that contain molecules of water. These compounds are known as
Hydrates.
The water stored within the hydrate is known as Water of Hydration.
Water of hydration can be removed from an associated ionic compound by heating. When the water is removed the
ionic compound is referred to as Anhydrous.
Writing Formula for Hydrates:
The chemical formula for hydrates indicates the number of associated water molecules after the molecule.
For Example: Hg(NO3)2 · H2O
- this mercury(II) nitrate is associated with one water molecule.
Naming Hydrates:
1. Name the ionic compound
2. Add the word “hydrate” with a Greek prefix (mono-, di-, tri-, etc.) indicating the number of water molecules
associated with the ionic compound.
For example: CoCl2 · 6 H2O is named cobalt(II) chloride hexahydrate.
Complete the following table of Hydrates using the IUPAC system.
Chemical Name
manganese(II) chromate
pentahydrate
Chemical Formula
Chemical Name
Chemical Formula
MnCrO4 · 5 H2O
calcium sulfate dehydrate
CaSO4 · 2 H2O
Mg(NO3)2 · 6 H2O
iron(III) chloride hexahydrate
FeCl3 · 6 H2O
SnCl2 · 2 H2O
barium hydroxide octahydrate
Ba(OH)2 · 8 H2O
mercury(I) nitrate
dihydrate
HgNO3 · 2 H2O
chromium(III) bromide hexahydrate
CrBr3 · 6 H2O
lead(II) perchlorate
trihydrate
Pb(ClO4)2 · 3 H2O
copper(II) perchlorate hexahydrate
Cu(ClO4)2 · 6 H2O
copper(II) acetate
monohydrate
Cu(C2H3O2)2 · H2O
magnesium sulfate heptahydrate
MgSO4 · 7 H2O
manganese(IV)
periodate
Mn(IO4)4 (oops
forgot the water!)
iron(II) fluoride tetrahydrate
FeF2 · 4 H2O
barium chloride
dihydrate
BaCl2 · 2 H2O
copper(II) chloride dihydrate
CuCl2 · 2 H2O
magnesium nitrate
hexahydrate
tin(II) chloride
dihydrate