Naming Multivalent Compounds

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Naming Multivalent Compounds
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What are multivalent ions?

• Some transition metals can form more than one ion
• In other words some have more than 1 ion form

For Example Copper has 2 ion forms Can be a
1 or 2 ion
Copper I Chloride
Copper II Chloride
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Writing Multivalent Compounds
Use roman numeral to show which ion form is
present
Metal Ion charge Roman Numeral 1 I 2 II
3 III 4 IV 5 V 6 VI 7 VII
Ni2 or Nickel II, is called Nickel two
Fe3 or Ion III, is called Iron three
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Steps for writing formulas for multivalent
compounds

• Step 1 Identify each ion and its charge
• Step 2 Determine the total charges needed to
  balance positive and negative
• Step 3 Note the ratio of positive ions to
  negative ions
• Step 4 Use subscripts to write the formula, 1s
  are not shown in subscript

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Example Copper II Chloride
Cu2 and Cl-
ions
2 -1-1
Total charge to balance
ratio
1 2
formula
CuCl2
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Example Manganese IV Oxide
Mn4 and O-2
ions
4 -2-2
Total charge to balance
ratio
1 2
formula
MnO2
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Steps for naming compounds that contain a
multivalent metal

• Step 1 Identify the multivalent metal (first ion
  written in formula
• Step 2 verify that it has more than one ion form
• Step 3 determine the ratio of ions in the
  formula
• Step 4 what is the charge on the negative ion?
• Step 5 what must be the charge on the positive
  metal ion if it is to balance the negative ion
• Step 6 write the name of the compound

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Example Au3N
Au
ID the metal
Au and Au3
Can it be in more than 1 ion form?
Au3N 3 Au ions for every 1 N ion
Determine the ratio of ions in the formula
Charge on the negative ion
N3-
If there are 3 Au ions then the charge on Au
must be 1 to balance out N3-
What does the charge on the metal have to be to
balance the negative ion?
The Name is Gold(I)Nitride