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Ch.21 - Transition Elements and Coordination Chemistry
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Not the one you use?Change textbook
All textbooksMcMurry 8th EditionCh.21 - Transition Elements and Coordination ChemistryProblem 21.127a
Chapter 21, Problem 21.127a

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)

Verified step by step guidance
1
Identify the oxidation state of the metal ion in the complex. For [AuCl_4]^2-, determine the oxidation state of Au.
Determine the electron configuration of the free metal ion. For Au, consider its position in the periodic table and its electron configuration.
Draw the orbital diagram for the free metal ion, showing the distribution of electrons in its d orbitals.
Consider the geometry of the complex (square planar) and determine the hybridization of the metal ion. Identify which orbitals are involved in hybridization.
Draw the orbital diagram for the metal ion in the complex, showing the hybrid orbitals and the number of unpaired electrons.

Key Concepts

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

Valence Bond Theory

Valence Bond Theory (VBT) explains how atoms in a molecule bond by overlapping their atomic orbitals. It emphasizes the role of hybridization, where atomic orbitals mix to form new hybrid orbitals that can accommodate bonding pairs of electrons. This theory helps in predicting the geometry of molecules based on the types of hybrid orbitals involved.
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Valence Shell Electron Pair Repulsion Theory

Hybridization

Hybridization is the process of combining atomic orbitals to create new hybrid orbitals that are suitable for the pairing of electrons to form chemical bonds. In the case of the square planar complex [AuCl4]2-, the gold ion undergoes dsp2 hybridization, utilizing one d orbital, one s orbital, and two p orbitals to form four equivalent hybrid orbitals for bonding.
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Hybridization

Unpaired Electrons

Unpaired electrons are electrons that occupy an orbital singly rather than in pairs. The presence of unpaired electrons is crucial for determining the magnetic properties of a complex and its reactivity. In the context of [AuCl4]2-, analyzing the electron configuration of the gold ion before and after hybridization helps identify the number of unpaired electrons, which influences the complex's overall behavior.
Related Practice
Textbook Question

Draw a crystal field energy-level diagram, assign the electrons to orbitals, and predict the number of unpaired electrons for each of the following.

(a) [Cu(en)3]2+

(b) [FeF6]2-

(c) [Co(en)3]3+ (low spin) 

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Textbook Question

What is the systematic name for each of the following ions?

(a) [MnCl4]2-

(b) [Ni(NH3)6]2+

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Textbook Question

Six isomers for a square planar palladium(II) complex that contains two Cl-and two SCN-ligands are shown below.


(a) Which structures are cis-trans isomers?

(b) Which structures are linkage isomers?

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Textbook Question

Assign a systematic name to each of the following ions.  

(a) [AuCl4]-

(b) [Fe(CN)6]4-

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Textbook Question

Draw a crystal field energy-level diagram for the 3d orbitals of titanium in [Ti(H2O)6]3+]. Indicate the crystal field splitting, and explain why is [Ti(H2O)6]3+] colored.

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Textbook Question

Cobalt(III) trifluoroacetylacetonate, Co(tfac)3, is a sixc oordinate, octahedral metal chelate in which three planar, bidentate tfac ligands are attached to a central Co atom:

(a) Draw all possible diastereoisomers and enantiomers of Co(tfac)3.

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