1. Transition Metals & Complex ions
State and give examples of complexes with six-fold coordination with an octahedral shape
Describe and use the terms: complex ion and coordination number.
Explain the term ligand in terms of coordinate bonding.

2. Definition Hangman – Coordinate bond (aka – dative covalent bond)
A shared pair of electrons in which the bonded pair has been provided by one of the bonding atoms only.
_ / _ _ _ _ _ _ / _ _ _ _ / _ _ / _ _ _ _ _ _ _ _ _ / _ _ / _ _ _ _ _ / _ _ _ / _ _ _ _ _ _ / _ _ _ _ / _ _ _ / _ _ _ _ / _ _ _ _ _ _ _ _ / _ _ / _ _ _ / _ _ / _ _ _ / _ _ _ _ _ _ _ / _ _ _ _ _ / _ _ _ _.

3. Complex ion [Fe(H2O)6]2+
Each of the six H2O ligands forms one coordinate (dative covalent) bond to the central metal ion using a lone pair of electrons from its oxygen atom.
This complex ion has a coordination number of six (the number of coordinate bonds to the central metal ion)

4. Charges on complex ions
The overall charge of a complex ion is the sum of the individual charges of the transition metal ion and those of the ligands.
Name of ligand
Formula
Charge
Water
:OH2
None - neutral
Ammonia
:NH3
Thiocyanate
:SCN- -1
Cyanide
:CN-
Chloride
:Cl-
Hydroxide
:OH-
Example
State the formula and charge of the complex ion made from one Iron (II) ion and 6 cyanide molecules.
[Fe(CN)6]4-
All of these ligands are classed as monodentate ligands (i.e. They only donate one pair of electrons to the central metal ion)

5. Formulae Questions
State the formula & charge of each of these complex ions:
One copper (II) ion & four chloride ions
One iron (III) ion & five water molecules & a chloride ion.
One copper (II) ion & four ammonia molecules & two hydroxide ions
One cobalt (III) ion & four hydroxide ions
What is the oxidation number of the transition metal in each of these complex ions.
[Fe(CN)6]3-
[Co(SCN)4]2-
[Cu(CN)4(Cl)2]4-
[Ti(H2O)3OH]2+

6. 3D shapes of complex ions
Most common shape = octahedral ( 6 coordinate bonds)
BOND ANGLE = all 90o

7. 3D shapes of complex ions
The copper(II) and cobalt(II) ions have four chloride ions bonded to them rather than six, because the chloride ions are too big to fit any more around the central metal ion.
Less common shape = tetrahedral ( 4 coordinate bonds)
BOND ANGLE = all 109.5o

8. Shapes of complex ions Questions
For each of the 8 complex ions you worked with during “formulae questions” draw the 3D shape using the wedge shaped bonds, show the bond angles and name the shape.

9. Reminder – what is a stereoisomer?
Molecules or complexes with the same structural formula but with a different arrangement of the atoms in space.

10. Stereoisomerism in complex ions Cis–trans isomerism in [Co(NH3)4Cl2]+
Chloride ligands at 90o to each other
Chloride ligands at 180o to each other

11. 4 coordinate bonds – alternative to tetrahedral
Stereoisomerism in complex ions Cis–trans isomerism in [NiCl2(NH3)2]
4 coordinate bonds – alternative to tetrahedral
= Square Planar
BOND ANGLE = all 90o

12. Structure of cis-platin
Effective cancer treatment –
Thought to bind to and alter cancer cell DNA and therefore prevent their growth and reproduction
What is the formula for cis-platin?
Explain why this molecule uses the prefix “cis” in its name.