Page 72 - MODERN ELECTROCHEMISTRY

16 CHAPTER 1

simplified enough for physicists to approach them in a more exact way. However, the
connections between chemistry and physics (e.g., the study of liquids and gaseous
reaction kinetics) largely occur through the parent areas of chemistry (see Fig. 1.7),
for example, statistical and quantum mechanics. A direct connection to areas just
outside chemistry does not immediately follow, e.g., liquids and reaction kinetics.
In electrochemistry, however, there is an immediate connection to the physics of
current flow and electric fields. Furthermore, it is difficult to pursue interfacial
electrochemistry without knowing some principles of theoretical structural metallurgy
and electronics, as well as hydrodynamic theory. Conversely (see Section 1.5.2), the
range of fields in which the important steps are controlled by the electrical properties
of interfaces and the flow of charge across them is great and exceeds that of other areas
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in which physical chemistry is relevant. In fact, so great is the range of topics in which
electrochemical considerations are relevant that a worker who is concerned with the
creation of passive films on metals and their resistance to environmental attack is
scarcely in intellectual contact with a person who is interested in finding a model for
why blood clots or someone seeking to solve the quantum mechanical equations for
the transfer of electrons across interfaces.
This widespread involvement with other areas of science suggests that in the
future electrochemistry will be treated increasingly as an interdisciplinary area as, for
example, materials science is, rather than as a branch of physical chemistry.
At the same time, there is a general tendency at present to break down the older
formal disciplines of physical, inorganic, and organic chemistry and to make new
groupings. That of materials science—the solid-state aspects of metallurgy, physics,
and chemistry—is one. Energy conversion—the energy-producing aspects of nuclear
fission, electrochemical fuel cells, photovoltaics, thermionic emission, magnetohydro-
dynamics, and so on—is another. Electrochemistry would be concerned with the part
played by electrically charged interfaces and interfacial charge transfers in chemistry,
metallurgy, biology, engineering, etc.

1.6. THE FRONTIER IN IONICS: NONAQUEOUS SOLUTIONS
Studies of ionic solutions have been overwhelmingly aqueous in the hundred
years or so in which they have been pursued. This has been a blessing, for water has
a dielectric constant, of ~80, about ten times larger than the range for most
nonaqueous solvents. Hence, because the force between ions is proportional to
the tendency of ions in aqueous solutions to attract each other and form groups is
relatively small, and structure in aqueous solutions is therefore on the simple side. This
enabled a start to be made on the theory of ion–ion attraction in solutions.
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As apart from areas of basic science (e.g., quantum mechanics) that primarily originate in physics and
underlie all chemistry, including, of course, electrochemistry.