Transition Metals and Coordination Chemistry

[OBJECTIVES: After having completed this unit, students should be able to:

Define, explain and/or give an example of the following:

• central ion (transition metal ion)
• metal complexes
• complex ion
• ligand
• coordination sphere
• coordination number
• geometry

Describe the structure of coordination compounds including: the central atom, ligands, metal complex, coordination number, geometry, and oxidation number.

Write electron configurations for transition metal atoms and metal ions.

Define isomerism and give an example.

Distinguish between structural isomerism and stereoisomerism. (note: Optical isomerism is NOT covered)

Identify and draw structures for the following types of isomerism: structural, stereoisomers, coordination sphere, linkage and geometric.

State the basic assumptions of the crystal field model.

Explain how the electrostatic interaction between the ligand and the metal’s d-orbitals in an octahedral field results in the splitting of the energy levels.

Explain the splitting of the energy levels in a tetrahedral complex and the reason for the smaller crystal field splitting compared to the octahedral complexes.

Draw d-orbital splitting diagrams for octahedral and tetrahedral complexes.

Distinguish between high and low spin complexes and strong and weak field octahedral complexes.

Explain the origin of color in complexes using d-orbital splitting.

Explain the significance of the spectrochemical series.

Given a spectrochemical series, predict whether a complex ion is more likely to have weak or strong crystal field splitting.

Explain how the colors of substances are related to their absorption and reflection of incident light.

Know the characteristic colors of the following common transition metal ions: Fe³⁺, Ni²⁺, Cu⁺, Cu²⁺, Co²⁺, Mn⁷⁺, Mn⁴⁺

Explain how crystal field theory can be used to predict whether a complex is diamagnetic or paramagnetic.

Predict the number of unpaired electrons in a high and low spin octahedral complex and determine if that complex is diamagnetic or paramagnetic.

Reading and Homework Exercises

Table of Contents from: OpenStax Chemistry 2e: Chapter 19

Introduction

19.1 Occurrence, Preparation, and Properties of Transition Metals and Their Compounds

Question 1:

19.2 Coordination Chemistry of Transition Metals

Question 2: For the coordination compound [Cr(H₂O)₆]Cl₃:

Question 3:  For the coordination compound K₃[Fe(C₂O₄)₃]:

Questions 4-7: A coordination compound has the following:

• Zn²⁺ is the transition metal ion
• two water molecules and two ammonia (NH₃) molecules as ligands
• Bromide (Br^–) as the counter ion

Question 4:

Question 5:

Question 6:

Question 7:

Questions 8-11:A coordination compound has the following:

• Mn²⁺ is the transition metal ion
• two water molecules and two ethylenediamine (en) molecules as ligands
• Bromide (Br^–) as the counter ion

Question 8:

Question 9:

Question 10:

Question 11:

Question 12:

Question 13:

Question 14:

Question 15:

19.3 Spectroscopic and Magnetic Properties of Coordination Compounds

Questions 16-18 use the spectrochemical series shown below:

Spectrochemical series (listed from smaller splitting (Δ) to larger Δ).

• I^1-
• Br^1-
• Cl^1-
• F^1-
• OH^1-
• H₂O
• NH₃
• en
• NO₂ ^1-
• CN^1-

Question 16:

Question 17:

Question 18:

Question 19:

Question 20:

Question 21:

Question 22: