nomenclature C~H~.NHXN~(CN)~
ammania/benzene/nickel(II) cya-
nide (11111~) The previous practice was to use the colon in place of the solidus to denote the ratio of numbers. Example
BFa2H20 baron trifluoride-water (1:2) An alternative method for indicating the ratio of constituents in an addition compound is by the use of numerical prefixes ( 4 ) . Example UniverGty of South Florido Tamp.
Chemical Abstrocl%Service
KURT LOENING ROY M. ADAMS
33620
Columbu%,Ohio 43210 Genera College
Bearer
Folls, Pennsylvonio
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~(CH&S.BIOCISH~ bis(dimethy1sulfide)-hexachlorodecaborane (8) This method is particularly useful to avoid any posiible conl'uaion with other n~tmhrrsenclosed in parentheses-in this mse the numher of hydrogen atmns in t h r parent borsne. There is no general agreement on the order of citation of the ...... of an addition nmoound. The Red Rook states: nmsriruenti "Boron compounds and water are always cited last in that order. Other molecules are cited in order of increasing number; any which occur in equal numbers are cited in aldhabetical order." However. horon chemists have always preferred to list is included in the "donor" molecule first (3)and such a those for inorganic horon compounds ( 4 ) . ~
Addition Compounds Deeply ingrained in the fabric of chemistry since the time of Lavoisier is the concept of two unlike molecules reacting to form a new species. Among such compounds are hydrates: CaS042HzO; ammoniates: NaC1.2NH3; and molecular addition compounds: EtzO.BF3. The structure of such compounds is well known and they can he given names to indicate these structures. [Ca(H20)21SO1 [Na(NHhICI RFaOEt2
diaquacalcium sulfate diamminesodium chloride (diethyl ether)trifluorohoron
The need for general terms to include all compounds with "water of crystallization" and all compounds with "ammonia of crystallization" has led to the wide-spread use of "hydrates" and "ammoniates" for this ourpose. However, the extension of this practice has certain pkfails since the ending -ate is now the accepted ending for anions generally. Hence, alcoholates are the salts of alcohols rather than compounds with "alcohol of crystallization." Quite aside from these donor-acceptor complexes, there is a wide variety of lattice or clathrate compounds. In these, spatial rather than chemical considerations dominate. While the stoichiometry for each of these is definite, the ratios are seldom simple. Thus, there is need for a general pattern of nomenclature to deal with these addition compounds, specifically, and all addition compounds, generally. The names of addition compounds are formed by connecting the names of individual compounds by spaced hyhens (IUPAC) ( I ) or by the solidus or slash (ACS) (2) and indicating the number of molecules after the name by Arabic numerals separated by the solidus. Examples
3CdSOeXHsO AI2(SO&KzSOc24HzO, BiCldPCIs XKr.46H20
cadmium sulfate-water(318) cadmium sulfatelwater (318) aluminum sulfate-potassium sulfate-water (111124) bismuth trichloridelphosphorus pentachloride (113) krypton-water (8146)
354, / Journal of Chemical Education
Examples
NH3.B3H7 ~(CH~)~N.BI&IN
ammonia-triborane(7) bis(trimethylan?ine)-dodecahorane(l0)
Boron chemists have also introduced another practice. If there are possible alternatives in the manner of attachment to the horon or if it is desirable to emphasize the of the lieand " manner of attachment, the dash (or solidus) between the molecular constituents is reolaced hv oarentheses enclosing the symbols of the two elements forming the bond separated by a dash. Examples
OC-BHB CH3ONH2.BHj
carbon monoxide (C-B)borane O-methylhydroxylamine(N-Rlborane
Literature Cited .. 11973). 13) Dawdmn, N..and Brown, H.C . d Amm Chsm. Sor.. 64.317 119421. (4) .'NomendatweofInorganic BamnCompaunds."R~reAppppl. Chrm.. 30 (3d!, c f l n o r g Chem., 7 1101.1952 1196Ri.
69911972):
Historical Development of Chemical Nomenclature Historians of chemistry have devoted comparatively little attention to nomenclature. The one serious study (1) does not extend beyond the Geneva Conference (1892).Consequently, some recent articles bv P. E. Verkade entitled "Historical - - - - ~ ~ Studies on the ~ o m e n c k u r of e Organic Chemistry" are most welcome. Professor Verkade was a member of the Commission on the Nomenclature of Organic Chemistry for half a century and its chairman during most of that time. Thus he writes from first-hand knowledge. The titles of the individual articles are ~
~~
I. The birth ofthe Genevanomenclature (1892).the nomenclature proposals of Saint-Etienne (1897). and the pertinent literature ( 2 ) . 11. The development of organic chemical nomenclature during the period 1889-1897 (3). 111. The facts and events relative to the nomenclature of organic chemistry during the period 1897-1911 (4). IV. The activities of the International Association of Chemical Societies in organic chemical nomenclature, 1911-1914 (5). V. Activities of individuals in the field of organic chemical nomenclature durine.. the oeriod 1914-1930 (6). . 1 The crrntion of the 1.iPge nornenclati~re(7). \'I1 l'hecontentsofthe I.i&genomenclaturecompared to that of the Geneva nomenclature (8). VIII. The facts and events relative to organic chemical nomenclature during the period 1930 to 1946 (9). . IX. Activity of the International Commission during the period 19461957 (10). X. On the content of Sections A and B of IUPAC Nomenclature of Organic Chemistry (11). XI. On Combes procedure (1892) for the nomenclature of acyclic compounds containing "complex functions" (12). XII. On the history of the creation of Section C of IUPAC Nomenclature of Organic Chemistry (13). ~
~~~
~
~
Llterature Cited
regard is t h a t of Chemical Abstracts ( C A ) .This journal regularly provides information on nomenclature rules-mostly IUPAC-in its introductions t o the index guides. Chemical Abstracts Service is also a source for reprints of nomenclature-related articles and rules. A major effort to make the rules of nomenclature simpler resulted in the changes in nomenclature policies for the 9th Collective Indexing Period (1972-76) (1 ). Reprints of the introduction outlining these changes ( 2 ) , can be purchased a t a price which make it the biggest bargain in nomenclature literature. For IUPAC publications on nomenclature see previous Notes (3). The Association for Science Education has prepared a summarv of chemical nomenclature (both inorganic and organio, symhols and terminology for use in Hritish schools r4). In Scotland, the Sational Curriculum Uevelo~mentCenter for Mathematics and Science has provided guidance t o teachers on the same topics ( 5 6 ) . The Division of Organic Chemistry of the American Chemical Societv had under preparation over a period of vears a manual on the nomenclaiurk of organic c h e m i s t r y . ~ h i s appeared early in 1974 (7) and has proved to be very popular. Writers of many recent inorganic textbooks (8-14) have made commendable efforts t o provide summaries of the IUPAC rules for inorganic nome&ature. Organic textbooks usually devote considerable attention t o nomenclature b u t a recent book does a particularly commendable job (15).
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Literature Cited N..Powell. W. H., Rowlott, R. J.. Jr.. White, R. W.. and Yorka, K. V.. J . Chem.Doc.. 11 11),9 119741. 121 "Namingsnd Index~ngolChemicalSuhdtlntltlfff Chemiiil AhdfraeUduringtheNinth CollectivePeriod (1972-19761," Chrm. Absrr, 76.211 11972). 131 Ferneliun, W. C., Loening, K., and Adams, R. M.,J. CHEM. EDUC., 50,341 119731; 52.483 119751. (4) .'Chemlcsl Nomenelsture. Symhols and Terminvlcxy: The Assncistim for Science Education, College Lane, Hatfield, Horts., U.K.,1972.66 pp. (5) "Chomicsl Nomenclature: Memorandum No.2. National Curriculum Development centre far Mathematic6 and science. Dundee College of F.ducation, Park Place. DundeeDDI4 HP. 1971. l l pp. (61 "Chemical Symbols and Formulae." National Curriculum Development Centre for Mathematier and Science. Dundee College oiEdueafion. Park Place. Dundee OD1 4 HP, 1971.18 p p 171 FieVher. J. H.. Dermer.0. C..and For. R. B.."Nnm~nciaturenfO?ganicCompounds." Advances in Chemistry Series No. 126. Am. Chem. Snc.. Wsshinnon. D.C., 1974. pp. 337. (81 Bsrrow,G. M.,"General Chemistry." Wadrwonh Publishing Company, Inc. Belmont. Ca. 1972. pp. 7.1146. (91 Busch. D. H., Shall. H..and Conley. R. T.,"Chemirtry."All~and Bacon. he., Bmton. Mass., 1913.p~.555-58. 1101 Doudas. B. E.. and McDanie1.D H.."Conceptpand Modelsof Inorganic Chemistry," Blaisdell Publishing Company. New York. N.Y.. 1965, pp. 466-75. (111 Garrett. A. B.. Lippinrott. W. T.,and Verhopk. F. H.. "Chemiriry: A Study ofMetter," 2nd. Ed.. Xerox College Publishing. Lexington. Mass.. 1972, sppendix pp. IV-VI. 1121 Huheey, J.E.;'lnorganicChemistry:Plinciplor"fStructureandResctivity,"Harper and Row. New Yurk.N.Y.. 1972, pp.fi74-9fl. 1131 Jones, M. M.,"Elementary Coordination Chemistry: Prentice~HallInc. Englewnd Cliffs. N.J. 1964.0n. 9-22, (141 Quagiiano. J. V., and Vallerinu. L. M.. "Cuordinsrian Chemistry." D. C. Heath and Company,Lorin@ifon, Mass., 1969.p~.4-9. (151 Sfsey. G. W.. "Organic Chemistry. A Background for the Life Sciences," Harper and Row, New York, 1975. (11 Donddsan.
Information Sources for Nomenclature Practices If names are not correct, language will not he in accordance with the truth of things. Confueius. Those who are devoted t o t h e cause of eood nomenclature are often dismayed t h a t their colleagues &e sometimes a bit good names. Gentle chidine careless in the use of " - in such cases uncovers such reasons as: There is no copy of the Rules in our library. (Unfortunately, this is all too often true). Too much time is required to learn all the detailed rules. Why don't you folks prepare a shortened and usable set of rules instead of encyclopedias with such minute details? In contrast t o these comments, one also hears frequently t h a t presentations of nomenclature practice do not provide either sufficient detail or enough examples. In this kind of climate it is gratifying t o record some significant recent efforts to make the rules simpler and/or more generally available. T h e most significant contribution in this
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Volume 53, Number 6,June 1976
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