POLYVALENT BINARY
IONIC COMPOUNDS
Unit 6: Ch 7.1b & Ch 9.2b
CRISS-CROSS METHOD
• Determine the ions
• Criss Cross the charges of the ions =
chemical formula
• Example:
Calcium + Phosphorus
CRISS-CROSS METHOD
• Determine the ions
• Criss Cross the charges of the ions =
chemical formula
• Example:
Calcium + Phosphorus
– Ca + P
• IONS = Ca2+ + P3-
CRISS-CROSS METHOD
• Determine the ions
• Criss Cross the charges of the ions =
chemical formula
• Example:
Calcium + Phosphorus
– Ca + P
• IONS = Ca2+ + P3Ca3P2
POLYVALENT METALS
• Many but not all transition metals have “multiple
personalities”
– # of valence electrons varies
• Polyvalent
– they can form more than one ion
• Roman Numerals are used to signify the charge
TRANSITION METALS
POLYVALENT TRANSITION
METALS
• Metals with more than one possible charge:
• Specific charge is indicated in parenthesis
POLYVALENT METALS &
BONDING
• Fe(II) =
– Iron (II) + oxygen =
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
• Fe2+ & O2-
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
• Fe2+ & O2-  Fe2O2  FeO
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
• Fe2+ & O2-  Fe2O2  FeO
• Fe(III) = Fe3+
– Iron (III) + oxygen =
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
• Fe2+ & O2-  Fe2O2  FeO
• Fe(III) = Fe3+
– Iron (III) + oxygen =
• Fe3+ & O2-
POLYVALENT METALS &
BONDING
• Fe(II) = Fe2+
– Iron (II) + oxygen =
• Fe2+ & O2-  Fe2O2  FeO
• Fe(III) = Fe3+
– Iron (III) + oxygen =
• Fe3+ & O2-  Fe2O3
NAMING POLYVALENT IONS
• Stock Name:
– Same as Simple Binary Ionic
– Plus metal’s oxidation #/charge (roman
numeral) in parentheses
• Fe2+  Iron (II) ion
• Fe3+  Iron (III) ion
NAMING POLYVALENT IONS
• Classical Name:
– Uses root word (typically from Latin name) with
different suffixes for different oxidation #’s/charges
• -ous  lower ionic charge
• -ic  higher ionic charge
– Example:
• Iron  Ferrum
– Fe2+  Ferrous ion
–Fe3+  Ferric ion
– Pg 255  List of classical names – Take down
the roots of the listed metals!
NAMING POLYVALENT BINARY
IONIC COMPOUNDS
• Same as Simple Binary Ionic Compounds
– Combine the ion names
• FeO
– Stock Name: Iron (II) Oxide
– Classical Name: Ferrous Oxide
• Fe2O3
– Stock Name: Iron (III) Oxide
– Classical Name: Ferric Oxide
PRACTICE - POLYVALENT COMPOUNDS
• Names to Formulas
– Silver (III) Nitride
– Silver (II) Nitride
– Vanadium (III) Chloride
– Vanadium (II) Chloride
– Lead (IV) Oxide
– Lead (II) Oxide
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– Fe2O3 
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– Fe2O3  Fe3+ and O2-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– Fe2O3  Fe3+ and O2• Check the anion’s charge against the periodic
table
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– Fe2O3  Fe3+ and O2• Check the anion’s charge against the periodic
table
– O2- is correct  So Fe is a 3+
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– Fe2O3  Fe3+ and O2• Check the anion’s charge against the periodic
table
– O2- is correct  So Fe is a 3+
–Name  Iron (III) oxide or Ferric Oxide
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– FeO 
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– FeO  Fe1+ and O1-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– FeO  Fe1+ and O1• Check the anion
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– FeO  Fe1+ and O1• Check the anion
–O1- is NOT correct  Been a reduction
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
– FeO  Fe1+ and O1• Check the anion
–O1- is NOT correct  Been a reduction
–1:1 ratio – metal started with the same charge as
the anion.
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3 
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3  Sn3+ and O1-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3  Sn3+ and O1O2-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3  Sn3+ and O1-
x2
O2-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3  Sn3+ and O1-
x2
Sn6+
O2-
PRACTICE - POLYVALENT COMPOUNDS
• Formula to Name
– Have to determine the oxidation #/Charge of
your metal.
• Reverse the criss cross (doesn’t always work)
–SnO3  Sn3+ and O1-
x2
Sn6+
O2-
–Name: Tin (VI) Oxide