Traditionally, when one deals with crystals, the first property to be presented is the periodicity of the lattice, and all methods of study are based on this characteristic, which is considered essential. In fact, crystals differ from the molecules of finite size that are studied in chemistry, only in their extremely large number of particles. Furthermore, the existence of faces, which limit the spread of crystals in space, necessarily breaks the periodicity of the system. For these reasons it is natural to apply to crystals the concepts and methods that have been widely tested in the study of molecules. Pauling first emphasized this point 1 and used it to explain the electronic structure of crystals, thought to be infinite and perfect. The aim of this work is to show, with the help of a few examples, the possibilities offered by quantum chemistry for tackling the problems of crystal electronic structure, of crystallographic arrangements as well as their macroscopic shape, and of distortion effects caused by the presence of faces. The area related to the existence of energy bands (allowed or forbidden), gap, electric, magnetic or optical properties will not be touched upon.

There are more than 20 million chemicals in the literature, with new materials being synthesized each week. Most of these molecules are stable, and the 3-dimensional arrangement of the atoms in the molecules, in the various solids may be determined by routine x-ray crystallography. When this is done, it is found that this vast range of molecules, with varying sizes and shapes can be accommodated by only a handful of solid structures. This limited number of architectures for the packing of molecules of all shapes and sizes, to maximize attractive intermolecular forces and minimizing repulsive intermolecular forces, allows us to develop simple models of what holds the molecules together in the solid. In this volume we look at the origin of the molecular architecture of crystals; a topic that is becoming increasingly important and is often termed, crystal engineering. Such studies are a means of predicting crystal structures, and of designing crystals with particular properties by manipulating the structure and interaction of large molecules. That is, creating new crystal architectures with desired physical characteristics in which the molecules pack together in particular architectures; a subject of particular interest to the pharmaceutical industry.

The Second Edition of Giant Molecules presents an introductory textbook on large molecules that exhibit specific physical and biological properties related to their size, orientation, and environment, making this subject accessible to students from high school to universities. Written by Charles Carraher, author of more than forty books on the subject, this up-to-date guide presents material in an integrated fashion, marrying fundamentals with illustrative applications. The text assumes no previous formal scientific training, and includes new and updated questions and answers, a glossary of relevant terms, bibliographies, visual aids, and related Web links in every chapter. Giant Molecules, Second Edition will appeal to individuals who have a personal or professional interest in polymers, as well as to college chemistry and materials science students who study polymers.

The French chemist Marcelin Berthelot put forward a classical and by now an often cited sentence revealing the quintessence of the chemical science: "La Chimie cree son objet". This is certainly true because the largest number of molecular compounds were and are continuously synthesized by chemists themselves. However, modern computational quantum chemistry has reached a state of maturity that one can safely say: "La Chimie Theorique cree son objet" as well. Indeed, modern theoretical chemistry is able today to provide reliable results on elusive systems such as short living species, reactive intermediates and molecules which will perhaps never be synthesized because of one or another type of instability. It is capable of yielding precious information on the nature of the transition states, reaction paths etc. Additionally, computational chemistry gives some details of the electronic and geometric structure of molecules which remain hidden in experimental examinations. Hence, it follows that powerful numerical techniques have substantially enlarged the domain of classical chemistry. On the other hand, interpretive quantum chemistry has provided a conceptual framework which enabled rationalization and understanding of the precise data offered either by experiment or theory. It is modelling which gives a penetrating insight into the chemical phenomena and provides order in raw experimental results which would otherwise represent just a large catalogue of unrelated facts.

?? Giant molecules are important in our everyday life. But, as pointed out by the authors, they are also associated with a culture. What Bach did with the harpsichord, Kuhn and Flory did with polymers. We owe a lot of thanks to those who now make this music accessible ??Pierre-Gilles de GennesNobel Prize laureate in Physics(Foreword for the 1st Edition, March 1996)This book describes the basic facts, concepts and ideas of polymer physics in simple, yet scientifically accurate, terms. In both scientific and historic contexts, the book shows how the subject of polymers is fascinating, as it is behind most of the wonders of living cell machinery as well as most of the newly developed materials. No mathematics is used in the book beyond modest high school algebra and a bit of freshman calculus, yet very sophisticated concepts are introduced and explained, ranging from scaling and reptations to protein folding and evolution. The new edition includes an extended section on polymer preparation methods, discusses knots formed by molecular filaments, and presents new and updated materials on such contemporary topics as single molecule experiments with DNA or polymer properties of proteins and their roles in biological evolution.

This book is a printed edition of the Special Issue "Liquid Crystals" that was published in Materials

An introduction to materials science for engineering students at the undergraduate or advanced technical college level. This second edition includes expanded material on ceramics and composites, plus study questions. Covers crystals, mechanical properties, the deformation of materials, phase equilibrium, stress failure, methods of joining, and nond

This latest edition of The Pearson General Studies Manual continues to provide exhaustive study material for the General Studies paper of the UPSC Civil Services Preliminary Examination. This student-friendly book has been completely revised, thoroughly updated and carefully streamlined and is strictly exam-centric. In this new edition, a large number of new boxes and marginalia—with additional and relevant information—have been added to provide cutting-edge information to the aspirant. Readers will find that important facts and information have been presented in the form of well-structured tables and lists.