Errors

Every book contains errors. Some are small, some are big. Some text isn't even strictly speaking wrong, but just misleading. The following is a list of errors and texts that might be misunderstood in the book used in this course. They are ordered with respect to the pages on which they can be found.

Oxtoby, Gilles, and Nachtrieb
Principles of Modern Chemistry

pages 61:
Equations should be valid whatever units are used for the quantities in an equation. This holds for the one but last equation on this page, and the reference to the energy unit can be removed. The last equation should be ignored.

pages 64:
One should not have the impression that there is a substantial amount of rearrangement of electrons when a chemical bond is formed. In general this rearrangement is quite small. A small rearrangement is sufficient to cause the energy lowering that corresponds to the bond energy. This energy is always a very small portion of the total energy of a molecule.

page 66:
Figure 3.7 is fine, but the text may be a bit confusing. If the electron is between the nuclei, then the net force on the left nucleus is to the right, and the net force on the right nucleus is to the left. If the electron is to the right of the nuclei, then the net force on the left nucleus is to the left and the net force on the right nucleus is to the right, thus pushing the nuclei apart.
You should be very suspicious about this simple explanation of the chemical bond. Consider this. Why should the electron want to be between the nuclei? Its potential energy has a maximum there. Changes in the kinetic energy of the electrons are often also very important in bond formation.

page 74:
Pauling's electronegativity is only defined up to a constant term.

page 75:
The percent ionic character is a rather meaningless quantity.

page 76:
The electrostatic argument to explain the repulsion between electron pairs is rather odd. Why should the Coulomb repulsion between the electron pairs be more important than the Coulomb repulsion between the two electrons forming one pair? A more correct, but also more complicated, explanation is that Pauli repulsion is responsible for the repulsion between the electron pairs.

page 505:
Energy need not be quantized. A free particle can have any positive value for its energy. And even if we have a system (an atom or molecule for example) for which the Schrödinger equation has only discrete solution for the energy, one should realize that the solutions of the Schrödinger equation are not the only possible wave functions. Other wave functions exist with a continuous range of energies. The interpretation of quantum mechanics in the book is too simplistic and incorrect.

page 513:
Planck used only idea (2).

page 524:
Between equations [15.8] and [15.9] there is a "nu". This should be a "v".

page 526:
The indices "f" and "i" in the denominators in equation [15.12] for adsorption should be swapped.

pages 528:
In the discussion there is no vibrating string with n=0. There are differences with the real orbitals. The vibrating circle with n=1 has a node. Its energy corresponds with the ground state of the hydrogen atom, which has n=0 and which does not have a node.

page 530:
The story about measuring and the uncertainty principle is not convincing. First, it seems to indicate a possible problem with measuring something not with an intrinsic uncertainty of a system. Second, even if you do change the momentum during a measurement, it does not mean that you cannot measure it.

page 531:
The analogy between a wave function and an electromagnetic field is incorrect. Electric and magnetic field can be measured.

page 531:
Again it is incorrect to state that the energy can have only discrete values.

pages 532:
The continuity of a wave function has nothing to do with the interpretation in terms of probabilities, but with the fact that it must be a solution of a differential equation (i.e., the Schrödinger equation).

page 532:
A free particle shows that the energy need not be quantized. The particle in a box is not the simplest Schrödinger equation.

page 534:
In the equation at the bottom of the left column there is a second n_x, which should be n_z.

page 535:
Between equations [15.21a] and [15.21b] there is a reference to equation [15.8b]. This equation does not exist. It should be equation [15.10b].

page 535:
The Schrödinger equation does not quantize the angular momentum operators. If we make linear combinations of the solutions of the Schrödinger equation for the hydrogen atom with the same n quantum number, then we get other solutions of the Schrödinger equation. These new solutions do not quantize de angular momentum operators. The solutions of the Schrödinger equation with quantum number n, l, and m do quantize the angular momemtum operators. There is a reason why it is possible to have such solutions, but that would lead us too deeply into the theory of quantum mechanics.

page 536:
In the figure the number between the square brackets [ ] indicate the degeneracy of the level.

page 538:
The angular functions in Table 5.2 are not Y(l,m)'s, but S(l,m)'s ( see the lecture notes). They do not quantize L_z, but they have the advantage that they are real-valued functions. The Ypx should have a second sin instead of a cos, and for Ydxy it should be sin(2j) instead of sib)2j.

page 538/539:
The volume of a spherical shell should be multiplied by 4p.

page 567:
The electronic energy alone cannot be the potential energy function for the interaction between the nuclei. The Coulomb repulsion between the nuclei has to be added.

page 570:
It makes no sense to talk about the energy in a molecular orbital. It is the energy (an electron in) a molecular orbital. The sentence that the energy in a molecular orbital reaches in minimum in the middle between the nuclei is nonsense.

page 571:
Point (3) is questionable (see the remark above relating to page 66 and the previous remark). Point (6) is incomplete. There are also other orbitals.

page 572:
In figure 16.4 the electron density seems to increase everywhere when a bonding orbital is formed. This is not possible, of course.

page 574:
The antibonding orbital is figure 16.8, and also in the following figures, is too low. The antibonding orbital shifts more upwards than the bonding orbital shifts downwards with respect to the original orbitals. This explains the repulsion between noble gas atoms.

page 576:
Overlap is not an interference property. Interference has to do with adding wave function. Overlap has to do with integrating a product of wave functions. Interference can have an effect at a certain position (e.g., destructive interference). Overlap is obtained after averaging (integrating) over the whole space.

page 579:
Assigning figure 16.11a and figure 16.11b to specific molecules is not as straightforward as the book says it is. It depends for example on the quality of the quantum chemical calculations, and it can depend on the precise definition of the term molecular orbital energy.

page 583-589:
This section deals with hybridization. This concept plays an important role in Valence Bond theory, but the section has nothing to do with Valence Bond theory.

page 589:
The inner C atoms of 2-butene has sp²-hybridization.

page 592:
The number of nodes of the orbitals of the pi-system of benzene is 0, 1, 2, and 3 (not counting the nodal plane that coincides with the plane of the molecule).

page 595:
In SCF the total wave function is not a product (because that would violate the Pauli principle), but a Slater determinant. It is also not necessary to write the orbitals in LCAO-form.

page 595:
The name SCF refers to a way to solve the Fock or Roothaan equations. However, there are other ways to find the solutions of these equations that are not iterative. The name may therefore be considered chosen badly.

page 595:
The difference between figure 16.31 (page 595) and the hybrid orbital picture only indicates different ways of looking at the chemical bonding, but does not reflect any limitations.