The First Edition of the Condensed Chemical Dictionary appeared in 1919 when the chemical industry in the United States was entering a huge expansion program as a result of World War I. The urgent need for such a reference book became apparent to Francis M. Turner, president of the Chemical Catalog Company, predecessor of the Reinhold Publishing Corporation. Under his supervision a succession of editors developed and expanded the Condensed Chemical Dictionary to meet the growing needs of the chemical industry. Since his death this development has continued, with the result that the work has achieved worldwide recognition in its field.

The Condensed Chemical Dictionary is a unique publication. It is not a dictionary in the usual sense of an assemblage of brief definitions, but rather a compendium of technical data and descriptive information covering many thousands of chemicals, chemical phenomena, and chem-biological materials organized in such a way as to meet the needs of those who have only minutes to devote to any given substance or topic.

Four distinct types of information are presented: (1) descriptions of chemicals, raw materials, processes, and equipment; (2) expanded definitions of chemical entities, phenomena, and terminology; (3) descriptions or identifications of a wide range of trademarked products used in the chemical industries; (4) definitions of bio-chemical materials, phenomena, and terminology. Supplementing these are listings of accepted chemical abbreviations used in the literature, short biographies of chemists of historic importance, and winners of the Nobel Prize in Chemistry. Also included are descriptions or notations of the nature and location of many U.S. technical societies and trade associations. In special cases, editorial notes have been supplied where it was felt necessary to clarify or amplify a definition or description. A few entries written by specialists are acknowledged by use of the author's name.

In a work of this nature, selection of topics for inclusion can hardly fail to be influenced by current interests and developing concerns within the topic area. The growing importance to scientists, public officials, and general public, of environmental and health hazards, which came to the forefront so quickly in the 1960s, was reflected in the Eighth Edition, which greatly increased its coverage of this aspect of chemistry.

Since then, the magnitude of the energy problem has been uppermost in the thinking of a broad spectrum of engineers, chemists, and physicists because it is certainly the most important technical problem confronting this country.

Both the Ninth and Tenth Editions, while retaining emphasis on environmental considerations, were expanded in the area of energy and its sources, as far as permitted by available information. The goal of the editors was to provide condensed, authoritative, factually oriented statements and descriptions, and to resist prognostications as to the future potential of any particular energy source. At the same time, continuing attention has been devoted to common hazards, such as flammable and explosive materials, poisons, pesticides, carcinogens, corrosive agents, and radioactive wastes, in line with the practice followed in earlier editions, and with the increasing public concern over these matters.

The Eleventh Edition added new chemicals, revised the format for chemical entries, and added new trademarked products and definitions. Chemical Abstract Services (CAS) numbers were included for many chemical entries to facilitate recourse to computerized databases.

In the Twelfth Edition, all trademarked entries were revised. The method of referencing was changed from superscripted numbers to the company names, facilitating access to the addresses of the manufacturers of trademarked products. Many additional definitions and cross-references were added to make the work current with the constantly growing field of chemistry.

In the Thirteenth Edition, all trademarked entries were revised and all CAS numbers verified. Many additional chemical entries, definitions, and cross-references were added to make the work current with the constantly growing field of chemistry.

In the Fourteenth Edition, links to the Internet were added. World Wide Web page addresses were added for manufacturers and associations in the appropriate entries and in Appendix III. Trademarked entries and their associated manufacturers were updated to reflect the constant flux in the modern chemical industry. Many additional chemical entries, definitions, and cross-references have been added to make the work current with the constantly growing field of chemistry.

In the Fifteenth Edition, over 4200 new or updated entries were included. Special effort was directed to add definitions and terms of art for biochemistry. Over 700 entries reflecting the great interest in biochemistry are now included. Over 90 terms relating to nanotechnology were added. Almost 3000 new chemicals were added, including trade named products. Links to World Wide Web page addresses for manufacturers and associations in the appropriate entries and in Appendix III were verified or added. Trademarked entries and their associated manufacturers were updated to reflect the constant flux in the modern chemical industry.

In the Sixteenth Edition, there is significant expansion of both chemical and biochemical terms. The reason for the additions of biochemical terms in the Sixteenth Edition is the emerging fields in biology and biological engineering such as synthetic biology, which highlight the merging of the sciences of chemistry and biology such that biology can be engineered to produce chemical substances and vice versa. In all, there are 1471 new definitions, 5236 revised or updated definitions, a new Chemical Abstract Number Index, and an update of all trademarks. Internet links were removed, except in certain instances; Internet search engines have become so powerful that it is no longer difficult to find relevant material about a particular chemical on the Internet.

In connection with certain classifications of substances, particularly pesticides and carcinogens, the statement “Use may be restricted” indicates that a state or local regulation may exist, even though a product has not been officially banned, or that a definitive ruling on its use is pending. When a product has been banned outright, the statement “Use has been prohibited” is used. A number of disputed cases have arisen in recent years; although some have been definitely settled, others are still being evaluated.

In such a work as this, in view of the many materials in various stages of evaluative testing, court procedures, appeals, hearings, and so forth, it is impossible to keep abreast of every development, every new chemical, and even every new biological organism. The user should check the current status of any questionable products/materials before making decisions that involve them (see Hazards below).

Chemicals, Raw Materials, and Biological Entries

The information in the categories listed next is given for each substance in the sequence indicated; where entries are incomplete, it may be presumed that no reliable data were provided by the reference systems utilized.

• Name: The commonly accepted name is the key entry. Terminological variations are indicated where necessary. In virtually all cases, the name is given in the singular number. A name having initial caps and enclosed in quotes is a trademark (TM). The manufacturers of trademarked products are indicated directly after the name in italics and within brackets (e.g., [Du Pont]). The addresses of the manufacturers are given in Appendix III.
• Synonym: Alternative names, as well as trivial names, are indicated. Obsolete and slang names have been eliminated as far as possible. Most synonyms are entered independently and cross-referenced, but space limitation has not permitted complete consistency in this regard.
• Chemical Abstract Service Registry Number (CAS): This universally used number permits use and comparison of data on a given material even though published under different synonyms. It will, in fact, permit absolute identification of a compound with all of its synonyms. CAS numbers also facilitate extraction of information from computerized data bases.
• Formula: The molecular (empirical or atomic) formula is regularly given. Structural formulas are used in special cases of unusual importance or interest.
• Properties: The properties typically given are physical state, atomic number, atomic weight, valence, isotopes, odor, taste, density, boiling point (at 760 mm Hg unless otherwise stated), melting point (freezing point), refractive index, and solubility or miscibility. Various other properties are given where pertinent: flash point, autoignition temperature, electrical properties, tensile strength, hardness, expansion coefficient, and so forth.
• Source or Occurrence: Geographical origins of metals, ores, essential oils, vegetable oils, and other natural products may be given.
• Derivation: The chemical reactions or other means of obtaining the product by current industrial methods are emphasized. Obsolete and “curiosity” methods have been largely eliminated.
• Grade: Recognized grades are provided as reported in the industrial literature, including technical, CP, USP, refined, reactor, and semiconductor.
• Hazard: This category includes flammability, toxicity characterization, explosion risks, and so on.

The ACGIH^® classifies carcinogens in five categories. confirmed human carcinogen, indicating the evidence is compelling for causing human cancer; suspected human carcinogen, indicating the substance is carcinogenic in animals but convincing evidence for human carcinogenesis is lacking; animal carcinogen, indicating the substance is carcinogenic in animals; not classifiable as a human carcinogen, indicating inadequate data are available to make a decision; and not suspected as a human carcinogen, indicating the available data do not suggest the likelihood the substance causes cancer. The ACGIH does not classify all potential carcinogens and some carcinogens may be listed as possibly carcinogenic.

It was not considered practical to include occupational exposure recommendations made by the National Institute for Occupational Safety and Health or exposure standards established by the Occupational Safety and Health Administration, as these are readily available on the Internet.

The toxicity ratings are intended to be used only as indications of the industrial hazard presented by a given material, as most of them are based on tests made on laboratory animals. Qualified toxicologists, industrial hygienists, exposure scientists, or physicians should be consulted for specific evaluations, dosages, exposure times, and concentrations. For further information regarding these hazards, the reader is referred to the following entries: combustible material; flammable material; dust, industrial; corrosive material; oxidizing material; poison; toxicity; toxic materials; and carcinogens.

• Use: These are primarily large-scale applications. Because of the rapidity of change in the chemical industries and the difficulty of obtaining reliable current data, no attempt has been made to list uses in the order of their tonnage consumption. The patent literature is not specifically represented.

General Entries

It is likely that no two editors would completely agree about what general subjects should be included in a dictionary of this kind. The major subdivisions of matter directly involved with chemical reactions, the various states of matter, biochemical materials, and the more important groups of compounds would almost certainly be regarded as essential, but beyond these, the area of selectivity widens rapidly. The topics either added or expanded by the present editor were chosen chiefly because of their interest and importance, both industrial and biochemical, and secondarily because of the terminological confusion evidenced in the literature and in industrial practice. Regarding the latter, the reader is referred to the entries on gum, resin, pigment, dye, filler, extender, reinforcing agent, and homogeneous and combustible materials. In some cases, a position has been taken that may not be accepted by all, but is defensible and certainly not arbitrary. Even editors must acknowledge that the meanings and uses of terms often change illogically, and that such changes are usually irreversible.

Among the general entries are important subdivisions of chemistry; short biographies of outstanding chemists of the past, including winners of the Nobel Prize in Chemistry; numerous group definitions (barbiturate, peroxide); major chemical and physical chemical phenomena (polymerization, catalysis); functional names (antifreeze, heat-exchange agent); terms describing special material forms (aerosol, foam, fiber); energy sources (solar cell, fuel cell, fusion); the more important chemical processes; and various types of machinery and equipment used in the process industries. No general entry is intended to be encyclopedic or definitive, but rather a condensation of essential information, to be supplemented by reference to specialized sources. To present all this in useful and acceptably complete form has been a challenging, though often frustrating task, which the editor leaves with the uneasy feeling that, like the breadcrumbs in the Hatter's butter, some mistakes are likely to have got in as well. For any mistakes, we apologize in advance.

Trademarks

Continuing the policy of previous editions, an essential component of the Dictionary comprises descriptions of proprietary industrial products. The information was either provided by the manufacturers of these materials or taken from announcements or advertisements appearing in the technical press. Each proprietary name is enclosed in quotation marks, is stated to be a trademark (or brand name), and is followed by a portion of the name of the manufacturer of the trademarked product. Manufacturer names are displayed in italics and within brackets (e.g., [Du Pont]). The addresses of the manufacturers are given in Appendix III. We wish to thank the owners of these trademarks for making the information available. The space devoted to these is necessarily limited, as the constant proliferation and changes in trademarked products make it impossible to list more than a small fraction of them in a volume such as this.

The absence of a specific trademark designation does not mean that proprietary rights may not exist in a particular name. No listing, description, or designation in this book is to be construed as affecting the scope, validity, or ownership of any trademark rights that may exist therein. Neither the editor nor the publisher assumes any responsibility for the accuracy of any such description or for the validity or ownership of any trademark.

The editors would specifically like to acknowledge the contributions of the late Robert A. Lewis, who prepared much of the updated material in biochemistry and biology. For Robert's contributions, we are truly thankful.

A Request

Many corrections and suggestions have been made by readers from around the world during the long history of the earlier editions. The editors have always tried to acknowledge these to the best of their ability. They have welcomed this correspondence, for it has been an important source of information about the acceptance of the Dictionary by its readers. The present editor and publisher wish to encourage this reaction from the field, not only to permit corrections to be made in reprinted issues, but also to establish a basis for preparing future editions. All letters addressed to the publisher will be forwarded.

Michael D. Larrañaga