1. Chapter 24 Transition Metals & Coordination Compounds
Properties of Transition Metals
Review Electron Configuration
Trends in the Periodic Table
Coordination Compounds
The Basics
Example of Naming
Structure and Isomerization

2. Transition Metals contain e- in d Orbitals
Breath – slow down!

3. Why Are Transition Metals & Coordination Compounds Important?
Therapeutic drugs
Chemical Sensors
Coloring agents
Paints
Cosmetics
Biological Molecules
Hemeglobin
Chlorophyll
Gems (Jewelry & Technological Applications)
Rubies, Emeralds, Garnets, etc.
Lasers

4. 24.2 Properties of Transition Metals
Moderate to High Densities
Good Electrical Conductivity
High Melting Points
Moderate to Extreme Hardness
Due to the delocalization of d electrons in metallic bonding
Exceptions: Elements with filled d orbitals, which prevents d-d bonding.
Hg has a low melting point and is liquid at room temperature.

5. Electron Configuration
Increasing
Energy
(n-1)d
(n-2)f

6. Electron Configuration
[noble gas] ns2 (n-1)dx
[noble gas] ns2 (n-2)f14 (n-1)dx
Slow down - Breath

7. Electron Configuration
[Kr]
5s2
4d2

8. Atomic Size Decreasing Size Increas Ing S i ze

9. Atomic Size
Keep it simple! breath
Exception to the trend: Electrons in the f-orbitals are not effective at shielding outer shell electrons from nuclear charge. So, the outer electrons are held in close – this is known as lanthanide contraction.

10. Ionization Energy Increases Decreases

11. Ionization Energy
Exception to the trend: Note that 5d elements have a greater ionization energy. This is again due to outer shell electron being held closer to the nucleus, so it take more energy to pull them away.

12. Electronegativity Increases Decreases

13. Electronegativity
Au: EN = 2.4
Compared to
P: EN = 2.1 !!
Gold breath slow down
Exception to the trend: There is an increase in electronegativity from the 3d (1st row transition metals) to the 4d (2nd row transition metals).

14. Oxidation States
Scandium
In general, stability is found in full or half-full shells, and in a configuration that looks like a noble gas.

15. 24.3 Coordination Compounds
Complex Ion - Central Metal bound to one or more ligands
Ligands are Lewis Base* (electron donors) and can be either neutral or negatively charged
The charge on the complex ion is balance by counter ions of opposite charge
The combination of a complex ion and counter ions results in a coordination compound
*Corrected 2:30 pm)
David N. Blauch -

16. A Little Background
In 1893, Swiss chemist Alfred Werner came up with the idea that a central metal could have 2 types of interactions
Primary Valence – Oxidation State of the central metal
Secondary Valence – Number of molecules or ions directly attached to the central metal or Coordination Number
Example: [Co(NH3)6]Cl3
The Primary Valence or Oxidation State of Co is +3
The Secondary Valence or Coordination Number is 6 (6 ammonia ligands are directly attached to Co
Other cobalt(III) coordination compounds
[Co(NH3)6]Cl3
[Co(NH3)5Cl]Cl2
[Co(NH3)4Cl2]Cl

17. Coordinate Covalent Bonds
Lewis Acid-Base Adduct – the ligand donates it’s electrons to the empty metal orbitals to form a coordinate covalent bond L : M
Lewis Acid
Lewis Base
Adduct

18. Some Common Ligands

19. Chelating Agents
Ligands can have one or more bonding pairs of electrons
Monodentate
Bidentate or Polydentate
Complex ions with bidentate or polydentate ligands are chelates, and the coordinating ligands are chelating agents Co
EDTA is hexadentate

20. Geometries
Anne Marie Helmenstine, Ph.D., About.com Guide

21. Naming Coordination Compounds
[Mn(CO)(NH3)5]SO4
(neutral ligands are written before charged ligands in the formula)
Cation 1st
Name the ligands in alphabetical order
ammine
carbonyl
Add a prefix to indicate the number of ligands
pentaammine
Name the metal ion
Manganese(II)
Anion 2nd
Sulfate
Pentaamminecarbonylmanganese(II) sulfate

22. 24.4 Structure & Isomerism Isomers Structural Isomers Stereoisomers
Coordination Isomers
Linkage Isomers
Stereoisomers
Geometric Isomers
cis-trans
fac-mer
Optical Isomers
Same formula – different structures
Same connectivities –different spacial arrangements
Different connectivities
Ligands & counter ions trade places
Ligands coordinate in different ways
Different spacial arrangements
Mirror images

23. Structural Isomers Coordination Isomers
pentaamminesulfatochromium(III) bromide
pentaamminebromochromium(III) sulfate
David N. Blauch -

24. Structural Isomers Linkage Isomers
pentaamminenitrocobalt(III) ion
pentaamminenitritocobalt(III) ion
David N. Blauch -

25. Stereoisomers Geometric Isomers: cis-trans
cis-diamminedichloroplatinum(II)
trans-diamminedichloroplatinum(II)
David N. Blauch -

26. Stereoisomers Geometric Isomers: fac-mer
fac-triamminetrichlorocobalt(III)
mer-triamminetrichlorocobalt(III)
David N. Blauch -

27. Stereoisomers Optical Isomers
Mirror Images
Non-superimposable
Enantimomers
Chiral: optically active (rotates polarized light)

28. Chirality Determining Optical Activity
fac
mer
David N. Blauch -

29. Chirality Determining Optical Activity
Superimposable -
No optical activity