Coordination Compounds
They’re complex.
• A coordination compound is the result of a Lewis
acid-base reaction.
M+a +
Lewis Acid
x :L-b  [MLx]a-xb
Lewis Base Complex Ion
A coordination compound is an ionic compound
that includes a complex ion.
For example
“Ligand” =“tied on”
Cu+2 + 4:NH3  [Cu(NH3)4] +2
Lewis Acid
Lewis Base Complex Ion
The complex ion is a metal ion with ligands
“tied on” to it.
For example
Cu+2 +SO4-2 + 4:NH3  [Cu(NH3)4]SO4
• The same complex ion as part of a
coordination compound:
tetraamminecopper (II) sulfate
For example
You have seen that the anhydrous copper (II) ion
is colorless. In an aqueous system:
[Cu(H2O)6]+2 + 4:NH3 [Cu(NH3)4H2O] +2
…the copper (II) ion is already part of a complex
Remember hydrates?
• CuSO4•5H2O
Remember hydrates?
• CuSO4•5H2O
• Or is it….
[Cu(H2O:)5]SO4?
pentaaquocopper (II) sulfate
We use brackets around a complex
ion.
[complex ion]
• A coordination compound has a complex
ion (cation, anion or both!)
Naming a coordination compound
• Name the (+) ion first.
• Name (-) ion
• How do we name the complex ion?
• Start with the metal—state the oxidation
number.
• Use Latin roots and –ate ending when it is
an anion (- ion) .
• Prefixes (with numerical prefixes) show
ligands. Many ligands end in –o-.
• Special names when used as a ligand
Special names when used as a
ligand
•
•
•
•
•
•
H2O– aquoNH3– ammineCN- --cyanoCO --carbonylOH- --hydroxoChloro- iodo- bromo- etc.
• When using (en) or (EDTA), numerical prefixes
include: bis- for 2, tris- for 3, tetrakis- for 4
• Different ligands are listed in alphabetical
order (regardless of numerical prefix)