notes on nomenclature
Univcrlity of South Florid. Tampa 33620
KURT LOENING ROY M. A D A M
Chemical Abstrocls Senicc Columbus. Ohio 43210 Geneva College
Beaver Fdlr.
Pennrytvmio 15010
Introduction Why o Series of Discussions on Nomenclofure?
Chemists are very fortunr~tein that their science has had n systematic nomenclature almost from its incep tion. This has not been true for some other sciences and the resulting confusion at times has retarded the development of those sciences. However, chemical nomenclature is not static because our science is growing and changing. With these developments old words take on new mennings and new ones must be introduced to deal with new situations be they new types of combination, of reaction, of method, or of concept. For the elements one must have acceptable unchanging names. For compounds, one seeks patterns thnt are related directly to composition and structure. For compounds of some complexity, names which reproduce exactly the structure are not always easy to derive by simple rules. Hence exact nomenclature can become complicated. In such cases, the temptation to simplify by introducing trivial names is strong. Because chemists frequently communicate about compounds by means of structural formulas and diagrnms without using any names a t all, some iconoclasts suggest that names are really not necessary. revertheless, in the over-all picture of chemical communication and documentntion it is still necessary to refer to compounds by name. Systematic names, trivial names, trade names, acronyms, laboratory-code designations, abbreviations, etc., are all used for this purpose. However, to establish a clear record of identity and continuity of chemical compounds used in research, commerce,. and industry throughout the world, the need for a systematic nomenclature on an international basis has long been recognized. Because the subject of chemical nomenclature requires constant attention, there are several committees Eo~mn'sNOTF.: We are plemed to welcome Nola on iVomenclolure, a new bimonthly column, whirh in s much needed mldition to the aruwing list of features of TIM J ~ U I & N A Questions L. on this topic should he addrerwed to the authors.
charged either on a standing or an ad hoe basis with studying the problems both of long standing and of recent origin, with attempting solutions, with sampling opinion from potential users, and of making recommendations. Several of the divisions of the American Chemical Society have nomenclature committees to accomplish the above charges. These committees ultimately make their recommendations to the ACS Committee on Nomenclature which, in turn, recommends adoption to the Council of the Society for use in the Society's publications. Most nations active in chemistry have one or more nomenclature committees although the pattern is seldom as elaborate as in this country. On the international scene, several of the Divisions of the International Union of Pure and Applied Chemistry have commissions on nomenclature. Several nations and languages are represented on any one commission. The commissions receive suggestions and make their recommendations, keeping in mind always that a pattern of nomenclature should be adaptable to all languages of scholarship. The official version of rules formulated by these commissions are in English (sometimes French, also) and must be accepted by the Council of IUPAC. These rules are then transmitted for adoption (often after translation) by the national bodies cooperating with IUPAC. For the United States, this body is the Division of Chemistry and Chemical Technology of the National Academy of Science-National Research Council. A compilation of rules, no matter how elegant the binding of the book, seldom gives an adequate impression of the sweat, blood, and tears that went into the choice of nomenclature pattern or the reasons for a particular compromise. By and large chemists want to use accepted and/or "good" nomenclature. The reason why a person's temper rises or he feels thnt his suggestion 1vss ignored is thnt he does not always clenrly understand all the factors involved or does not see the consequences of hi suggestion on existing patterns of nomenclature outside the immediate problem he sought to solve. Hence, these brief notes on nomenclature will seek to add to the understanding of existing rules or problems by supplying historical perspective, by presenting vexing problems, and by extrapolation on the probable effectsof certain decisions. Some years back, Dr. Austin IM.Patterson, outstanding student of chemical nomenclature and leader in the adoption of sound practices a t both the national and international levels, presented a column on nomenclature in Clremical and Engineering News. The column wns entitled "Words about Words." Following Dr. Patterson's death, the substance of this column was collected and published 3s a single volume. Many of the discussions are relevant today. Possibly the biggest source of difficulty is the new system of nomenclature or the "fresh approach." Granted that there is a high probability of devising a Vohrme 48, Number
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better total pattern of nomenclature today than the one being used, should we attempt to do so? Given all the compounds known today it might just possibly be easier to devise a new scheme for nomenclature than to patch up the scheme presently in use. Before we embark on this engaging enterprise, however, let us ask a few questions. Can we be sure the new scheme will be sufficiently adaptable to acwmodate all the new compounds that are going to be discovered even before the scheme is completely formulated? What are we going to do about the handbooks and indexes which are the entree to existing knowledge? Do we revise these and reisaue them or do we ask all users of the literature to learn the old as well as the new scheme or do we just forget about what has been done before the year 1 NN (New Nomenclature)? What do we do when the new scheme is found to be somewhat inadequate? Start all over again? For all of these, who will pay the bii? Whatever the weaknesses of our present schemes, we are pretty much stuck with them. Whatever tinkering is done should be thought through very carefully. However, we should understand much better what we do have and why it was adopted. When we do understand it better, we probably will decide that what we have is not so bad after all. The international standard works on nomenclature are the Definitive Rules issued by the Commissions on Nomenclature of the International Union of Pure and Applied Chemistry. These first appear in the official organ of the Union, "Pure and Applied Chemistry," and later as separates in hard covers.
.mnic.
The Definitive Rules are often reprinted in a l e d i g journal of member countries of IUPAC. For example, the first item and first edition of the second item above were reprinted in the J o u m l of the American Chemical Society, 82,5523 and 5545 (1960). The Reports of the IUPAC Nomenclature Commissions are issued first as Tentative Rules in the Information Bulletins of the Union. Unfortunately, these Information Bulletins do not receive wide circulation. However, reprinting of Tentative Rules in the journals of member eompaniea is enwurnged. For example the tentative proposals for "Nomenclature of Absolute Configurations Concerned with Six-Coordinated Complexes Based on the Octahedron" which appeared in Information Bulletin No. 33, December 1968 were reprinted inlnorganic Chemistry, 9,1(1970). Likewise "Fundamental Stereoohemistry" (Section E of "Nomenclature of Organic Chemistry") which appeared in Information Bulletin No. 35, June 1969 was reprinted in The J o u m l of Organic Chemistry, 35, 2849 (1970) and Biochem. Biophys. Aclo, 208, (1970). In addition to the issuing of Tentative and Definitive Rules, all of the Commissions of the International Union prepare minutes of their work sessions. These 434
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are often published in the Comptes Rendvs of the Conference a t which these meetings took place. The national committees on nomenclature often issue reports. Two recent such reports from the ACS Committee on Nomenclature are "The Nomenclature of Boron Compounds," Inorganic Chemistry, 7, 1945 (1968) and "A Structure-Based Nomenclature for Linear Polymers," Macromolecules, 1,193 (1968). Two ACS publications are very helpful in matters of nomenclature. "The Handbook for Authors of Papers in the Journals of the American Chemical Society" (third edition, 1967) has a section on nomenclature in which a list of definitive and tentative rules as well as other relevant references is given. The Introduction to the Subject Index of Volume 56 of Chemical Abstracts entitled "The Naming and Indexing of Chemical Compounds" has been issued as a separate publication (1968). I t contains an abundance of examples and a detailed index. The "Combined Introduction" to the Indexes to Volume 66 of Chemical Abstracts complements the Intmduction to Volume 56. Special Publication No. 14 of The Chemical Society (London), "Handbook for Chemical Society Authors" (1960) is largely devoted to nomenclature. There are a few books by private authors which are devoted to nomenclature. A third edition of "Intmduction to Chemical Nomenclature" by R. S. Cahn, recently retired from the editorship of The Chemical Society (London), was issued in 1968 (Butterworths). A number of books have appeared recently to provide programmed instruction in nomenclature: "Inorganic Nomenc1ature"by R. L. Olsen (Burgess, 1%7), "Organic Chemistry Nomenclature" by 0. Runquist (Burgess, 1%5), "The Names and Structures of Organic Compounds" by 0. T. Benfey (John Wiley d: Sons, 1966), and "Naming Organic Compounds" by J. E. Banks (Snunders, 1968). "Historical Studies in the Language of Chemistry" by M. P. Crosland (Haward University Press, 1962) gives an account of the developments in nomenclature from the beginning of chemistry down to the present century. A few major articles (other than those givenin "The Handbook for Authors ACS") will prove useful to many. ADAM.. R. M.. "Cage Bomn Nonamehlun." I n o w . C b r . 2. 1087 (1M-3).
ADAM.. R. M.. "Nomen~latum Problems in Boron Chemiotry." I.Clem.
pp. 14780.
Avno. C. D.: "The Gananl Philaophy of Oreoia Nomenehtum." J. C n r r . Eooe.. 38, 43 (1961). Lor~ma.K. L.. "In~cmatianalCmp.~.ti~o on SeisntiBc Nomenohtun." 3 . Chm. D a ~ n w i o n 10, . 231 (1970). Lor~nro.K. L.. "Nomanchture" in Kirk-Othmsr Emyclodi. of C h e m i d Tschnolo(ly. Vol. 14 Intarsoianm Encyelopedi% 1.0. 1967, pp. 1-15, MCDOII=LL. P. M.. INU PI#TIIIICX. R. F.. "A Lime-Formnh NoUtion syatsm for Coordiaslion Compounds." J. C h m . Dorumentalion. 5. 56 (1065).
PASTIRWAR. R. F.. *no M c D o ~ n m b t P. . M.. "Dssimmlioa of
Liwnd Poi-
Camplcm." I n o w . Chrm.. 4. 6W (1065). S C O J. ~ .D.. "Noon t h e Nomcncl.lum of lnorganm Compounds." Inorganic Synthesss. 2, 157 (1916). tiom in Cmrdio.tion
