Ionic Nomenclature
Naming Ionic Compounds
Ionic Compounds Review
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Ionic compounds are made of positive
and negative ions.
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Also known as “salts”.
Polyatomic ions are groups of atoms
that behave as a single ion:
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Examples:
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CO3-2
CN-1
SO4-2
Naming Ionic Compounds
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Two types of ionic compounds:
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Binary, contains 2 elements
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NaCl, MgBr2, Fe2O3
Ternary, contains 3 elements
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Two of the elements are in a polyatomic ion
NaNO3, NH4Cl, Cr2(SO4)3
Naming Binary Ionic Compounds
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Some metal ions have only one possible charge:
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For fixed charge cations, name as element.
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Group 1A metal ions all have +1 charge.
Group 2A metal ions all have +2 charge.
Ag+1, Zn+2, Cd+2, Al+3, Ga+3
Na+1 = sodium ion
Ca+2 = calcium ion
Ag+1 = silver ion
Ga+3 = gallium ion
Name anion as stem of element’s name followed by
suffix –ide.
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Cl-1 = chloride ion
S-2 = sulfide ion
N-3 = nitride ion
Fixed Charge Metal Ions
Li+1 Be+2
Na+1 Mg+2
Al+3
K+1 Ca+2
Zn+2 Ga+3
Rb+1 Sr+2
Cs+1 Ba+2
Fr+1 Ra+2
Ag+1 Cd+2
Naming Binary Ionic Compounds
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NaCl
KBr
MgF2
CaO
AgI
Al2S3
Zn3P2
sodium chloride
potassium bromide
magnesium fluoride
calcium oxide
silver iodide
aluminum sulfide
zinc phosphide
Naming Binary Ionic Compounds
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Most metals can form multiple cations.
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Iron can form Fe+2 ions or Fe+3 ions.
Copper can form Cu+1 ions or Cu+2 ions.
For variable charge cations, name as
element w/ Roman numeral in ( ) to indicate
charge.
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Fe+2 = iron(II) ion
Fe+3 = iron(III) ion
Cu+1 = copper(I) ion
Cu+2 = copper(II) ion
Pb+2 = lead(II) ion
Pb+4 = lead(IV) ion
Variable Charge Metal Ions
Naming Binary Ionic Compounds
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The compound must be electrically neutral.
Use the charge of the anion to figure out the
charge of the metal.
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Example: Fe2O3
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(2 x Fe) + (3 x -2) = neutral
(2 x Fe) – 6 = neutral
(2 x Fe) = +6
Fe = +3
iron(III) oxide
Example: FeO
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Fe + -2 = neutral
Fe = +2
iron(II) oxide
Naming Binary Ionic Compounds
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FeCl2
Fe2Se3
CuBr
CuS
CrO
CrI3
PbF2
PbS2
iron(II) chloride
iron(III) selenide
copper(I) bromide
copper(II) sulfide
chromium(II) oxide
chromium(III) iodide
lead(II) fluoride
lead(IV) sulfide
Naming Ternary Ionic Compounds
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Name metal as you would for a binary, with
charge as a Roman numeral if necessary.
Name polyatomic anions as themselves.
Know these:
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CO3-2 = carbonate
NO3-1 = nitrate
PO4-3 = phosphate
SO4-2 = sulfate
OH-1 = hydroxide
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ClO-1 = hypochlorite
ClO3-1 = chlorate
C2H3O2-1 = acetate
CH3COO-1 = acetate
CN-1 = cyanide
Naming Ternary Ionic Compounds
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Only one polyatomic cation:
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NH4+1 = ammonium
Name it, then name the anion properly.
Naming Ternary Ionic Compounds
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LiNO3
Mg(OH)2
Fe2(SO4)3
Zn(C2H3O2)2
AlPO4
NH4Cl
Cr(CN)2
lithium nitrate
magnesium hydroxide
iron(III) sulfate
zinc acetate
aluminum phosphate
ammonium chloride
chromium(II) cyanide
Writing Formulas From Names
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To write an ionic formula from a name, write the
ions with their proper charges, then criss-cross.
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Write the formula for iron(III) hydroxide
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Don’t forget that polyatomic ions need parentheses if
there’s more than one of them.
iron(III) = Fe+3
hydroxide = OH-1
iron(III) hydroxide  Fe+3 + OH-1  Fe(OH)3
Write the formula for potassium sulfate
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potassium = K+1
sulfate = SO4-2
potassium sulfate  K+1 + SO4-2  K2SO4
Writing Formulas From Names
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calcium carbonate 
sodium oxide 
aluminum cyanide 
potassium acetate 
copper(II) hydroxide 
gold(III) sulfide 
Ca+2 + CO3-2 
Na+ + O-2 
Al+3 + CN-1 
K+1 + C2H3O2-1 
Cu+2 + OH-1 
Au+3 + S-2 
CaCO3
Na2O
Al(CN)3
KC2H3O2
Cu(OH)2
Au2S3