Naming Chemical Compounds
• Binary Compounds of Metals with Fixed
Charges (Ionic Compounds)
• Covalent Compounds of Nonmetals: The
Greek System
• Binary Compounds of Cations with
Variable Charges: Stock System
Naming Chemical Compounds
• Binary Compounds of Cations with
Variable Charges: Common Name System
• Polyatomics
• Acids
• Hydrates
Binary Compounds of Metals with
Fixed Charges
• Name the cation first then the anion
• Use the cation’s fixed charge directly from
the periodic table (eg. Ca+2 is Calcium)
• Name the anion using the root of the
element’s name plus the suffix “ide” (eg.
S-2 would be Sulfide)
• Examples:
• CaS would be Calcium Sulfide
• Na2O would be Sodium Oxide
• Potassium Chloride would be KCl
Covalent Compounds of
Nonmetals: The Greek System
• Name the first element: if there are two or
more, add a prefix to match the subscript
• Name the second element also using a
prefix to match the subscript (including
“mono-” for one)
• Prefixes: one=“mono-”, two=“di-”,
three=“tri-”, four=“tetra-”, five=“penta”,
six=“hexa-”, seven=“hepta-”, eight=“octa-”,
nine=“nona-”, ten=“deca-”
The Greek System
• Example 1: N2O
• Subscript for 2 is “di-” so it is dinitrogen
• Subscript for O is 1 so the name is dinitrogen
monoxide
• Example 2: N2O5
• Subscript for nitrogen is 2 so it is dinitrogen
• Subscript is 5 for oxygen or pentaoxide
• The name is dinitrogen pentaoxide (pentoxide is
also acceptable)
Binary Compounds of Cations with
Variable Charges: The Stock System
• Named for German
chemist Alfred Stock
• Cations involved have
at least two charges
• Anion has one charge
• Uses parentheses
and roman numerals
• Example: FeCl2 is
iron(II) chloride
The Stock System
• Name the cation’s element first
• Determine the charge by multiplying the
anion’s charge by it’s subscript; then divide
this by the cation’s subscript
• Example 1: Name CuCl2
• Chloride anion’s charge is -1 times it’s subscript 2
equals 2 (Ignore sign of -2)
• Divide by Copper’s subscript of 1 equals 2
• The result is Copper(II) chloride
The Stock System
• Example 2: Name Fe2O3
• Oxide anion’s charge is -2 times it’s subscript 3 equals -6
• Divide by Iron’s subscript of 2 equals 3
• The result is iron(III) oxide
• Example 3: Give the formula for manganese(IV)
oxide
• The cation’s charge is given from the formula +4
• Oxide’s charge is -2; Since the charge of the final formula
must be zero, two oxides or 2 times -2 equals -4 gives zero
net charge
• The result is MnO2
Binary Compounds of Cations with
Variable Charges: The Common Name
System
• Proposed by
Lavoisier “Father of
Modern Chemistry”
• Uses the Latin root of
the cation plus –ous
or –ic suffix to
indicate oxidation
state (-ous is lowest,
-ic is highest)
The Common Name System
• Find the root name of the first element
• Iron=“ferr-“, chromium="chrom-“, lead="plumb-”,
tin="stann-“, copper="cupr-“, cobalt="cobalt-“,
gold="aur-“, manganese="mangan-“,
mercury="mercur-“
• Multiply the charge of the anion by its
subscript (Ignore the sign)
• Divide by the cation’s subscript
• The lower of 2 values gives –ous; the
higher -ic
The Common Name System
• Example 1: Fe2O3
• Multiply oxide’s -2 times the subscript 3 equals 6
(ignore the sign)
• Divide 6 by iron’s subscript by 2 equals 3
• The result is ferric oxide (iron exists as +2 or +3)
• Example 2: Cu2S
• Multiply sulfide’s -2 times the subscript 1 equals 2
(ignore the sign)
• Divide by copper’s subscript 2 equals 1
• The result is cuprous sulfide
The Common Name System
• Example 3: Ferrous Oxide
•
•
•
•
Ferrous means +2
Oxide is -2
Use charge balance or criss-cross method to solve
Fe+2O-2 yields FeO
• Example 4: Stannic Phosphide
• Stannic means Sn+4
• Phosphide is P-3
• Sn+4P-3 yields Sn3P4
Polyatomics
• Naming can be either fixed or variable
charges
• When more than one polyatomic ion is
required, parenthesis must be used
• Example 1: Fe(NO3)2
• Decide if the cation has a variable charge (iron
does so you must determine the roman numeral)
• NO3 has a -1 charge so iron must be +2
• The name is iron(II) nitrate or ferrous nitrate
Polyatomics
• Example 2: Fe(OH)3
• Determine the charge of iron: Hydroxide is -1 so iron must be
+3
• The compound is iron(III) hydroxide or ferric hydroxide
• Example 3: Aluminum Phosphate
• Aluminum is a fixed-charge of +3
• Phosphate ion is PO4-3
• The formula is AlPO4
Binary Acids
• Binary acids are hydrogen with a non-metal
(binary acids include: HCl, HF, HBr, HI)
• “hydro-” STEM “-ic” is used (STEM comes from
the anion)
• The word acid is added at the end
• Examples:
• HCl is hydrochloric acid (STEM is chlor)
• HF is hydrofluoric acid
• HBr is hydrobromic acid
Oxy (Ternary) Acids
• Contains hydrogen and a polyatomic ion
• Change the “ate” ending to “ic” and the
“ite” ending to “ous” and add the word acid
• Polyatomic ion that ends in “ate”
• STEM –ic acid
• Example HClO3 = chloric acid
• Polyatomic ion that ends in “ite”
• STEM –ous acid
• Example HClO2 = chlorous acid
Oxy (Ternary) Acids
• Polyatomic ion with prefix “hypo”
• Hypo- STEM –ous acid
• Example HClO hypochlorous acid
• Polyatomic ion with prefix “per”
• Per- STEM –ic acid
• Example HClO4 perchloric acid
Hydrates
• Compounds that have water in them
• General Formula AB . xH2O
• Name the compound (AB) and add the
number of water molecules present (x
equals the coefficient)
• Examples:
• CuSO4 . 5 H2O is copper(II) sulfate pentahydrate
• MgSO4 . 9 H2O is magnesium sulfate nonahydrate
Reference
• See these web sites for practice!!!
• http://dbhs.wvusd.k12.ca.us/webdocs/Nomencl
ature/Nomenclature.html
• http://www.woodrow.org/teachers/chemistry/lin
ks/chem1/NamingComp.html