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Ch.21 - Transition Elements and Coordination Chemistry
All textbooksMcMurry 8th EditionCh.21 - Transition Elements and Coordination ChemistryProblem 21.128a
Chapter 21, Problem 21.128a

There are two possible [M(OH)4]- complexes of first-series transition metals that have three unpaired electrons.
(a) What are the oxidation state and the identity of M in these complexes?
(b) Using orbital diagrams, give a valence bond description of the bonding in each complex.
(c) Based on common oxidation states of first-series transition metals (Figure 21.6), which [M(OH)4]- complex is more likely to exist? 
<QUESTION REFERENCES FIGURE 21.6>-

Verified step by step guidance
1
Identify the first-series transition metals that can form [M(OH)_4]^- complexes with three unpaired electrons. Consider the electronic configuration of these metals in their common oxidation states.
Determine the oxidation state of M in the [M(OH)_4]^- complex. Since the hydroxide ion (OH^-) has a charge of -1, and the overall charge of the complex is -1, calculate the oxidation state of M.
For each identified metal, draw the orbital diagram for the valence electrons in the oxidation state determined. Show how the electrons are distributed among the d orbitals, ensuring there are three unpaired electrons.
Use valence bond theory to describe the bonding in each complex. Consider the hybridization of the metal's orbitals and how they overlap with the orbitals of the hydroxide ligands.
Refer to Figure 21.6 to compare the common oxidation states of the identified metals. Determine which metal is more likely to exist in the [M(OH)_4]^- complex based on its stability and prevalence in that oxidation state.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Oxidation States of Transition Metals

The oxidation state of a transition metal indicates the charge it would have if all ligands were removed, and all bonding electrons were assigned to the more electronegative atom. Transition metals can exhibit multiple oxidation states due to their ability to lose different numbers of d-electrons. Understanding the common oxidation states helps in predicting the identity of the metal in complexes and their stability.
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Transition Metals

Valence Bond Theory and Orbital Diagrams

Valence Bond Theory explains how atomic orbitals combine to form bonds in molecules. Orbital diagrams visually represent the distribution of electrons in these orbitals, showing how unpaired electrons can participate in bonding. For transition metal complexes, the arrangement of d-orbitals and their interactions with ligands are crucial for understanding the geometry and bonding characteristics of the complex.
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Molecular Orbital Diagram

Ligand Field Theory

Ligand Field Theory extends the concepts of Valence Bond Theory by considering the effect of ligands on the energy levels of d-orbitals in transition metals. It explains how the presence of ligands can split the d-orbital energies, influencing the number of unpaired electrons and the overall stability of the complex. This theory is essential for predicting the likelihood of certain oxidation states and the formation of specific metal-ligand complexes.
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Strong-Field Ligands result in a large Δ and Weak-Field Ligands result in a small Δ.
Related Practice
Textbook Question

Give a valence bond description of the bonding in each of the following complexes. Include orbital diagrams for the free metal ion and the metal ion in the complex. Indicate which hybrid orbitals the metal ion uses for bonding, and specify the number of unpaired electrons. 

(b) [NiBr4]2- (tetrahedral) 

Textbook Question

For each of the following complexes, describe the bonding using valence bond theory. Include orbital diagrams for the free metal ion and the metal ion in the complex. Indicate which hybrid orbitals the metal ion uses for bonding, and specify the number of unpaired electrons. 

(a) [AuCl4]2 (square planar)

Textbook Question

For each of the following complexes, describe the bonding using valence bond theory. Include orbital diagrams for the free metal ion and the metal ion in the complex. Indicate which hybrid orbitals the metal ion uses for bonding, and specify the number of unpaired electrons. 

(b) [Ag(NH3)2]+

Textbook Question

Two first-series transition metals have three unpaired electrons in complex ions of the type [MCl4]2-.

(a) What are the oxidation state and the identity of M in these complexes?

(b) Draw valence bond orbital diagrams for the two possible ions.

(c) Based on common oxidation states of first-series transition metals (Figure 21.6), which ion is more likely to exist?

<QUESTION REFERENCES FIGURE 21.6>

Textbook Question

Nickel(II) complexes with the formula NiX2L2, where X− is Cl− or N-bonded NCS− and L is the monodentate triphenylphosphine ligand P(C6H5)3, can be square planar or tetrahedral.

(a) Draw crystal field energy-level diagrams for a square planar and a tetrahedral nickel(II) complex, and show the population of the orbitals.

Textbook Question

Nickel(II) complexes with the formula NiX2L2, where X is Cl- or N-bonded NCS- and L is the monodentate triphenylphosphine ligand P(C6H5)3, can be square planar or tetrahedral.

(b) If NiCl2L2 is paramagnetic and Ni(NCS)2L2 is diamagnetic, which of the two complexes is tetrahedral and which is square planar?