Chemical sciences defined

A vital activity of the chemical sciences is the determination of structure. Detailed molecular structure determinations require identifying the spatial locations of all of the atoms in molecules, that is, the atomic distances and bond angles of a species. It is important to realize that the three-dimensional architecture of molecules very much defines their reactivity and function. However, molecules are dynamic, a feature that is not reflected by static pictures. This last point requires further explanation. Because the atoms in all molecules move, even in the limit of the lowest temperatures obtainable, molecular structures really describe the average position about some equilibrium arrangement. In addition, rotations about certain bonds occur freely at common temperatures. Consequently, some molecules exist in more than one structure (conformation). Some molecules are so floppy that structural characterizations really refer to averages among several structures. Yet other molecules are sufficiently rigid that molecular structures can be quite precisely determined. 

As the analytical, synthetic, and physical characterization techniques of the chemical sciences have advanced, the scale of material control moves to smaller sizes. Nanoscience is the examination of objects—particles, liquid droplets, crystals, fibers—with sizes that are larger than molecules but smaller than structures commonly prepared by photolithographic microfabrication. The definition of nanomaterials is neither sharp nor easy, nor need it be. Single molecules can be considered components of nanosystems (and are considered as such in fields such as molecular electronics and molecular motors). So can objects that have dimensions of >100 nm, even though such objects can be fabricated—albeit with substantial technical difficulty—by photolithography. We will define (somewhat arbitrarily) nanoscience as the study of the preparation, characterization, and use of substances having dimensions in the range of 1 to 100 nm. Many types of chemical systems, such as self-assembled monolayers (with only one dimension small) or carbon nanotubes (buckytubes) (with two dimensions small), are considered nanosystems. 

From a sampling of nineteenth-century statements about the aims of chemistry as a scientific discipline, Robert Friedel found the key words to be "composition," "properties," and "change." In Robert Friedel, "Defining Chemistry Origins of the Heroic Chemist," in Seymour Mauskopf, ed., Chemical Sciences in the Modern World. 

This workshop focused on factors such as work processes, systems, and technologies that could enable and accelerate the pace of innovation and increase the yield of major innovations from work in the basic chemical sciences. More specifically, speakers identified teamwork, commitment, standardized portfolio management, clear goals, well-defined milestones, and effective technology transfer as some of the characteristics of innovative institutions and practices. Successful approaches to innovation have taken place in different environments and between different environments—despite infrastmcture and cultural differences, both interdisciplinary collaborations and collaborations between industry and academia have proven beneficial for all parties. Funding must also be available to promote innovation at stages of research often ignored. 

Chapter 6 examines what, in the authors opinion, are three important applications of vacuum technology in the chemical sciences. First, its use in chemical technology is clearly defined and, in many applications, the requirement for systems operating below 10 6 Pa is obvious. In both cases, typical systems are considered and quantified. The third topic concentrates on a technique (differential pumping) which is widely used in systems where high- and low-pressure areas must be interfaced. Specific systems are discussed to illustrate the usefulness of the technique. 

In order to define the energy and transportation challenges and opportunities for the chemical sciences in the 21st century, the future needs can be divided into two time frames—midterm (through 2025) and long term (2050 and beyond).1 While these scenarios can be debated, the drives they create in the chemical sciences are not greatly affected by the severity of the scenarios. They do point to a... 

The Workshop on the Environment was held in Irvine, California, on November 17-19, 2002. This workshop was the third in a series of six workshops that make up the study Challenges for the Chemical Sciences in the 21st Century. The task for each of the workshops was defined as follows ... 

Green chemistry is defined as the practice of chemical science and manufacturing in a manner that is sustainable, safe, and nonpolluting, and it consumes minimum amounts of materials and energy while producing little or no waste material. The major aspects of green chanistry include the following ... 

Finally there is progress in science. Today problems often look different than formerly. In the field discussed here this is especially so for the polymorphism of chemical compounds. There are many phases of chemical compounds defined by different unit cell dimensions, symmetry and atomic coordinates... 

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