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Book Review Molecular Geometry. By R. J. Gillespie

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BOOK REVIEWS
The Radiation Chemistry of Macromolecules. Edited by Malcolm Dole. Vol. l . Academic Press, New York-London
1972. 1st Edit., xiv, 369 pp., numerous figures, bound
.$23.--.
The effects of high-energy radiation (electromagnetic radiation,
electronic radiation) on macromolecules have attracted both
scientific and technical interest. The first 11 of the 14 chapters
in this book deal on the one hand with the theoretical principles
of radiation chemistry and on the other with the physical
and chemical phenomena of the solid state.
The section on radiation chemistry is mainly concerned with
the primary processes induced in matter by ionizing radiation
and with the reactions of the resulting short-lived species
such as ions, excited molecules, and free radicals. Special
chapters are therefore devoted to the theory of free radicals
and to investigations on trapped electrons in organic glasses
and polymers with the aid of optical and ESR spectroscopy.
The treatment of molecular mobilities and electrical conductivity in polymers is followed by a discussion of the change
in the electrical conductivity in irradiated polymers. Another
chapter deals with the phenomenon of thermoluminescence
in polymers, which is still in its early stages as a field of
research. This is followed by a chapter on the statistical theory
of degradation and crosslinking, which are at present the
two most important technical processes involving the application of high-energy radiation to polymers.
The last three chapters deal with experimental technique and
the results of irradiation experiments on linear polyethylene
as the prototype ofa simple macromolecule. After the introductory theoretical chapters, this part of the volume will certainly
be welcomed, since it discusses practical results of radiation
chemistry and tries to correlate them with the complicated
morphology of polyethylene.
The book can be recommended to anyone seeking a general
picture of the processes that occur on irradiation of macromolecules. The many literature references will also help those
who wish background information on the material, which
is very difficult in part.
Christel Schneider [NB 206 IE]
Molecular Geometry. By R. J . Gillespie. Van Nostrand Reinhold Comp., London 1972. 1st Edit., ix, 228 pp.. numerous
figures and tables, bound ca. DM 38.In past monographs, inorganic structural chemistry has been
marked by the crystal-chemical approach. It is therefore all
the more commendable that the structure of isolated molecules,
together with inorganic stereochemistry, is given precedence
in the present book.
However, the general title forms a cover for the special
approach developed earlier by the author together with R .
S. Nyholm, the “valence shell electron pair repulsion theory”
(VSEPRT). This theory assigns spherical spaces around the
closed shell of the core electrons to pairs of free and valence
electrons as proposed by Bent, and derives the molecular
geometry from the magnitude of the electron pair repulsion.
This concept is presented and extended in the first third of
the book. It is remarkable that in a book with this title,
neither elements of group theory nor ideas such as orbitals
or hybridization are required in the development of a concept
of bonding and structure, a concept that will be greatly appreciated by the practical worker; S means sulfur, and never denotes either entropy or an axis of rotation-reflection. At the same
time, however, this is a danger of the book, which is undoubt-
556
edly intended to appeal mainly to students : alternative views
(such as the hypervalent bonding theory) are omitted altogether, or else an attempt is made in an appendix to provide
a connection with the MO approach. This becomes particularly clear in examples such as F-, which should not exist
according to p. 38, or in postulates such as that of a second
valence shell invoked to explain the paramagnetism of O2
(.{:O=O:). with a triple bond; pp. 84/85).
Thestrength of the book lies in the second part, which presents
an unusually thorough survey of the structural types of compounds, arranged according to elements of the first, then
the second and higher periods of the periodic system and
transition metals. Here again molecular structures take precedence over ionic lattices, and a large number of diagrams
(not always of uniform quality) are included for greater clarity.
The emphasis is clearly placed on non-tetrahedral and nonoctahedral structures; polyhedral structures are derived in
an understandable manner.
On the whole the book gives a competent subjective account
of inorganic stereochemistry, and can be recommended to
anyone who is familiar with the limitations of the VSEPRT
and with alternative approaches.
Hans Burger [NB 208 IE]
Metal n-Complexes, Vol. 11. Complexes with Mono-Olefinic
Ligands. By Max Herberhold. Elsevier Publishing Company,
Amsterdam-London-New
York. Part I : General Survey,
1972, 1st Edit., xv, 643 pp., 206 figs., 85 tables, bound ca.
D M 295.--. Part 2: Specific Aspects, 1974, 1st Edit., xvi,
508 pp., 106 figs., 51 tables, bound ca. D M 250.Hardly any other field has developed so rapidly over the
past 20 years as the chemistry of transition metal x-complexes.
Until now there has been no general survey of existing knowledge in the field of x-complexes with monoolefinic ligands.
The publication of both parts of a detailed monograph on
this subject is therefore very welcome. After a historical introduction, the first part deals with general preparative methods.
Two long chapters then describe the chemistry of transition
metal complexes with olefins, and specifically a) with olefins
having no functional groups (the material is arranged here
according to the metal) and b) with olefins containing functional groups (arranged according to the functional group).
The second part considers spectroscopic studies, X-ray structures, stability of the olefin complexes, the theory of metalolefin bonding, and the use of these compounds in industrial
processes.
The first part covers the literature comprehensively up to 1968.
An appendix lists 210 publications from the years 1969 and
1970; this gives some idea of the annual growth of this field.
In the second part, the literature up to 1970 is included, and
an appendix lists 239 further references from the period up
to the middle of 1972.
The plan of the first part is broad. Physical properties and
chemical reactivity are discussed in detail. Clarity is aided by
numerous tables and summaries in the form of formula
schemes. The overall impression reflects the author’s years
of experience in this field and his attention to detail.
Opinions may be divided with regard to the arrangement
of the material and the classification principle. In the reviewer’s
opinion, a discussion of the theory of metal-olefin bonding
at the beginning of the book would have helped the reader
to understand many of the systematic relationships. The brief
note on the historical development of bonding theories on
Angew. Chem. internat. Edit. J Vol. 13 (1974) / No. 8
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