The uses and abuses of bond energies

Abstract

The author argues that the concepts of bond energy and bond-dissociation energy be presented to undergraduate physical and organic chemistry students in enough detail that some real understanding results.

Trends in Bond Dissociation Energies for the Homolytic Cleavage of Successive Molecular Bonds

“…Considering that the making and breaking of chemical bonds is fundamental to the discipline, an important concept covered in all general and physical chemistry texts is that of bond energy. However, this concept is associated with several critical misconceptions − likely due to the confusing and misused terminology used in the instruction of the topic . For example, the phrase “energy stored in chemical bonds” can be confusing to students who may infer that this energy will be released as a result of bond breaking .…”

“…However, this concept is associated with several critical misconceptions 1−5 likely due to the confusing and misused terminology used in the instruction of the topic. 4 For example, the phrase "energy stored in chemical bonds" can be confusing to students who may infer that this energy will be released as a result of bond breaking. 2 On the other hand, use of the term bond "strength" is purely qualitative but is sometimes used as a synonym for bond energy.…”

“…2 On the other hand, use of the term bond "strength" is purely qualitative but is sometimes used as a synonym for bond energy. 4 The challenge increases when bond dissociation energy (BDE) is introduced. BDEs are particularly important for physical chemistry students to understand when they are introduced to radical chain reaction mechanisms in kinetics.…”

“…Knox defined bond energy as the "contribution of the bond between a particular pair of atoms...in a molecule to the total binding energy present in the molecule". 4 On the other hand, BDE corresponds to the energy change for the homolytic cleavage of a specified bond in the molecule:…”

Determination of bond energies by mass spectrometry: some transition metal carbonyls

“…The terra "bond energy" is one of the most misused terms in science [7]. The reason for this is not obvious because the phrase is correct conceptually.…”