Arrow Pushing in Inorganic Chemistry

A Logical Approach to the Chemistry of the Main-Group Elements

Abhik Ghosh, Steffen Berg

• Publisher: Wiley
• Year: 2014
• ISBN:
  9781118924532
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Inorganic Chemistry

Involved as it is with 95% of the periodic table, inorganic chemistry is one of the foundational subjects of scientific study. Inorganic catalysts are used in crucial industrial processes and the field, to a significant extent, also forms the basis of nanotechnology. Unfortunately, the subject is not a popular one for undergraduates. This book aims to take a step to change this state of affairs by presenting a mechanistic, logical introduction to the subject.

Organic teaching places heavy emphasis on reaction mechanisms - "arrow-pushing" - and the authors of this book have found that a mechanistic approach works just as well for elementary inorganic chemistry. As opposed to listening to formal lectures or learning the material by heart, by teaching students to recognize common inorganic species as electrophiles and nucleophiles, coupled with organic-style arrow-pushing, this book serves as a gentle and stimulating introduction to inorganic chemistry, providing students with the knowledge and opportunity to solve inorganic reaction mechanisms.
•The first book to apply the arrow-pushing method to inorganic chemistry teaching
•With the reaction mechanisms approach ("arrow-pushing"), students will no longer have to rely on memorization as a device for learning this subject, but will instead have a logical foundation for this area of study
•Teaches students to recognize common inorganic species as electrophiles and nucleophiles, coupled with organic-style arrow-pushing
•Provides a degree of integration with what students learn in organic chemistry, facilitating learning of this subject
•Serves as an invaluable companion to any introductory inorganic chemistry textbook

Chapter 1
A Collection of Basic Concepts

In solving a problem of this sort, the grand

thing is to be able to reason backward. That is

a very useful accomplishment, and a very easy

one, but people do not practise it much. In the

everyday affairs of life it is more useful to reason

forward, and so the other comes to be neglected.

Sherlock Holmes in A Study in Scarlet, By Sir Arthur Conan Doyle

We assume you've had an introductory course in organic chemistry and hope you found it logical and enjoyable. The logic of organic chemistry is of course key to its charm, and mechanisms are a big part of that logic. In this book, we will present a similar approach for inorganic chemistry, focusing on the main-group elements, that is, the s and p blocks of the periodic table (Figure 1.1). As in organic chemistry, our main tool will be the curly arrows that indicate the movement of electrons, typically electron pairs, but on occasion also unpaired electrons. As we shall see, this approach—arrow pushing—works well in inorganic chemistry, especially for the main-group elements.

Figure 1.1 The periodic table: group numbers and the s, p, and d blocks.

We want to get you started with arrow pushing in an inorganic context as quickly as possible, but we'd also like to make sure that you are equipped with the necessary conceptual tools. In this chapter, we'll try to provide you with that background as efficiently as possible. Unavoidably, the concepts form a somewhat disparate bunch but they do follow a certain logic. Sections 1.1–1.6 introduce the idea of nucleophiles and electrophiles, in the context of the S_N2 displacement, and discuss physical concepts such as electronegativity, polarizability, pK_a, redox potentials, and bond energies in relation to chemical reactivity. Armed with these concepts, we'll devote the next several Sections 1.7–1.21 to survey key mechanistic paradigms, focusing on major organic reaction types but also on a few special inorganic ones. Sections 1.22 and 1.23 then present practical tips on arrow pushing, that is, how you might approach a given mechanistic problem. In the course of our mechanistic survey, we'll encounter a number of so-called hypervalent p-block compounds, which you may not have encountered until now. These call for a brief discussion of the bonding involved, which we will present in Sections 1.24–1.27. That said, we will not cover some of the more elementary aspects of structure and bonding theory, including the very useful VSEPR (valence shell electron pair repulsion) model; feel free to go back to your general o...