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edited by MARY VIRGINIA ORNA,0.S.U College of New Rochelle New Rochelle. NY 10801
Ewens-Bassett Notation for Inorganic Compounds George B. Kauffman CaliforniaState University, Fresno Fresno. CA 93740 Chrlstian Klixbiill Jgrgensen DBpaRement de Chlmie Minerale. Analytique, et Appliqde Section Chimie, Sciences I1 Universle de Genhve 1211 Geneve 4, Suisse
In the course of reviewina our recent article on "The Origin and Adoption of the Stock System" ( I ) , oneof the referees klt that "it would he unfair to inrrodure anvone to Stock numbers without simultaneously introducing chat person to EwensBassett IE-Bl numbers," and the Editor of this feature suagested that we write a short note on the history and adoption of E-B numbers. We have already traced the various meetinm and published reports of the ~ o k m i s s i o non the ~ o m e n c l a ture of Inorganic Chemistry of the International Union of Chemistry (IUC) and the International Union of Pure and Applied Chemistry (IUPAC) elsewhere (2). I t suffices to mention that following meetinp in Herlin on January 28-29, 1938 and Home on May 16,1938, rhe Committee for the REform of Inoreanic Chemical Nomenclature of the~ IUC - - dww ~- ~ up a set of rules (the so-called 1940 Rules) published in German (3) and translated into English by Henry Bassett (4). At the first post-World War I1 meeting (London, 1947) of the revived IUC, which was retitled the IUPAC. nomenclature discussions were reopened by a Commission dn the Nomenclature of Inorganic Chemistry, which decided that the Commission's primary goal was to be an expansion and more precise formulation of the 1940 Rules (3.4). On the basis of these discussions, two members of the ~o&ission, H. Bassett ,~ in (Chairman) and R. V. G. Ewens ( S e ~ r e t a r y )published 1949 a widely disseminated and influential article (5)drawing attention to a number of problems in inorganic nomenclature and suggesting variouss&tions to thrsediff'irulties. Among the many proposals made in this -paper, which emploved a . . ~
~
~
Presented at the Symposium on History of Chemical Nomenclature, Division of History of Chemistry. 189th National Meeting, American Chemical Society, Miami Beach, Florida, April 30, 1985 Ronald Victor George Ewens was born in 1913, was educated at Cueen Elizabeth's Hospital. Bristol, and received his doctorate in 1938 from Lincoln College, Oxford University. as a pupil of Nevil Vincent Sidgwick (6).After a year's investigation of the inhibiion of fermentation and glycolysis by snake venom at the Sir William Dunn School of Pathology, Oxford,he became Demonstrator and later (1948)Reader in chemistry at Guy's Hospital Medical School. His primary research interest was metal carbonyls and nitrosyk. As Bassen told Fernelius, the 35-year-old Ewens committed suicide by throwing himself in front of a subway train on September 21. 1948, in the year preceding the publication of the paper (a.He len behind a widow and a young daughter. Henry Bassen (1881-1965). PhD. Munich; DSc, London; was Assistant Lecturer, Liverpool University; Professor and Head of the Department of Chemistry, University College, Reading and Reading University; and Emeritus Fellow, University College, London. He was primarily interested in double salts and solid ammoniates and was the author of "Theory of QualitativeAnalysis" and "Chemical Laboratory for Beginners" (7).
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The IrPAC Comm w o n on me homcnc i l l b r 6 ~of norqanlc Cnem lr, J I tr n Rcilumg 1956 From r o w tlrom lcftr W Fe lrnecnl n Remy. H Bassen. A So w r m n tCna man,. K. A. .snrcn. N elz B,e,r.m. G h. C h e e s ~ n
meellng
(Secretary).Back raw (from ten): A young chemist who served as a guide; Commission members E. H. Buchner. A. Slander,and J. Benard: and S. Veibel, obsewer from the Organic Commission. L. Malatesta also participated in the meeting but was not made titular member until 1959 (photo courtesy, K. A. Jensen, Kpbenhavns Universitet.) -
lettering and numbering system to conform to the corresponding paragraphs in the 1940 Rules, was the one with which we are concerned here--the use of numbers named Ewens-Bassett although they were originated by the then recently deceased Eweus alone. The 1940 Rules discarded the -ow, -ic suffix system of indicating valency and declared (46, p. 890): Indication of the electrochemical valency in the names of compounds should be made only by Stock's method. . . . by means of Roman figures, placed in parentheses and following,without hyphen, immediately after the names of the elements to which they refer. The Stock system was used not onlv for simnle comnounds but also toiconiplexes (wordination rompbunds) as well. Kwens and Rassett proposed that in cases where "this system hrcaks down.. . .complexities can be avoided, and a certain simplification in the nomenclature achieved if' the ioniccharge is indicated in surh cases (in Arahic numerals)" (5,p. 137). Although the exiitencr of lerovalent elements is well recognized today, they regarded surh an oxidation number as which they "meaningless" incompoundssuch as K,[N~(C'NJ~I, named powssium tetracyanonick~lare~-11rather than potassium tetracyanonickelate(01 (modified Stock system, 1940 Rules). They also cited ( 5 , p. 137 I complexes, where NO usually forms part of the complex, in which a true statement of valency or oxidation state of the metal is quite impossible bemuse of oxidation-reduction chanees - takine dace between the ligand and the central metal atom, such as Roussin's red salt, Kz[Fez(NO)&] (modern K 2 F e (NO)zS]z, black salt, K[Fe4(NO)&], and derivatives. They named the red salt potassium [tetranitrosyl disulpho difer-
ratel(-2)(8) (modern. tetranitrosvldithiodiferrate (2.)) . .. (9. .. sec;ibn 1.312). ~ l t h o u g Ewens h an2 Bassett did not mention it. zero is not used with unchareed comwlexes because of its use in the Stock system. (Since there is no symbol for zero in Roman numerals, the Arabic zero is used in the Stock system, but this was not specifically documented in the IUPAC rules until 1957 (10)). Ewens and Bassett also suggested that polyhalogen salts and salts of halopen- or sulfur-substituted oxv acids (5, D.
Beginning with a meeting a t Munich in 1959, the IUPAC Commission on the Nomenclature of Inorganic Chemistrv under the chairmanship of K. A. Jensen continued its work, which resulted in "Nomenclature of Inorganic Chemistry, 1970," a second edition of the "Red Book," published in 1971 (9). The 1970 Rules not only accepted the use of E-B numhers for horon hydride ionxand charges on coordinated ynnlpsas shown ahove but also prq)osed their use as an alternative to indicating the nxidation slaw hy a Roman numeral (9, Secrinn 2.252):
be named conveniently and satisfactorily hy making use of the -ate termination without valency significance and by adopting Ewens' system of showing the charge carried by the complex ion . .. [which is] particularly useful with the polyhalogen salts where it isnot easy ta state the valency of the central halogen.
The proportions of the constituents may also be indicated either by Stock's system or by the Ewens-Bassett system.. .
For example, they suggested the following names: KI3 potassium di iodo iodate(-1) (modern,diiodoiodate(1-)) KICL potassium tetra ehloro iodate(-1) (modem, tetrachloroiodate(1-1) CsIF6 caesium hexa fluoro iodate(-1) (modern, hexafluoraiodate(1-)) Na&Od sodium (mono)thiosulphate(-2) (modern, thiosulfate(2-)) BalCS4 barium trithiocarbonate(-2). (modern. trithiocarbon. ate&)) K[S03F]potassium monofluorosulphate(-1) (modern, monofluorosolfntell-1),, Kz[POaF] potassium monofluorophosphate(-2) (modern, monofluorophosphate(2-)) K[P02F2]potassium difluorophasphate(-1) (modern, difluoroUnfortunately, throughout Ewens and Bassett's paper all the occurrences of (-1) (Arabic numerals) were incorrectly typeset as Roman numerals, (-I) [sic], leading to a confusion of the Stock system with the Ewens-Bassett system! Ewens and Bassett (13) also suggested the use of their Arabic numerals to differentiate the two cations derived from hydrazine: NzHsf hydraz~nium(+l)~ (modem,hydrazinium) NzHsZ+ hydra~onium(+Z)~ (modern, hydrazinium(Z+)) Again, throughout the paper the typesetter incorrectly used (+I) (Roman) for (+I) (Arabic). Followins! further meetines of the Nomenclature Commission, a c&derably extenled set of rules was prepared and presented as "Tentative Rules" a t a conference in Stockholm in 1953 (14). They were adopted to supersede the 1940 Rules by the Council of the IUPAC a t a conference in Paris in 1957 and published two years later (11). Although the 1957 Rules did not adowt or even mention the E-B notation.. as wro~osed . . by K. A. ~ ~ n s ethey n , adopted E-B numbers in connection with the above-mentioned N2H5+ and NzH62+ ions, which they called hydrazinium(l+) and hydrazinium(2+), reversing the position of the Arahic numeral and sign (11, Section 3.17). E-B notation, nevertheless, with the reversed position of the numeral and sign, became an integral part of inorganic nomenclature for ions derived from the horon hydrides as well as for denoting the charge on ligands (101, for example, Nap[BloHlolsodium deeahydrodeeaborate(2-) [Mn{CsH1(0)(C00))2(Hz0)4]4bis[salicylato(2-)]tetraaquamanganate(II1) the latter name employing both E-B and Stock numbers. Two E-B numhers may also he used in naming the same species, e.g., (15)
[CO~CZHI[N(CH~COO)~I~INCSI~[ethylenediaminetetraacetate(4-)lthiocyanatoeobaltate(3-)
Chemical Abslracfscalled these ions hydrazonium prior to 1967. Since men ir calls them hydrazinium, the name used in the first ( 11)and second (9)editions of the "Red Book." See also References ( 12)and (131.
Some of the examples given are: KAFe(CN)61 NazNzOz FeCh
potassium heaaeyanoferrate(4-) sodium dioaodinitrate(2-) iron(2+) , , chloride dimercury(2+)chloride pentaamminechloroeobalt(2+) ion ~
~ g &
[CoCI(NH3)slZ+
~~~
While the 1957 Rules recommended the Stock names uranyl(V1) and uranyl(V) for the ions U022+ and UOzt, respectively (11, Section 3.32), the 1970 Rules also suggested the alternative E-B names uranvl(2+) for these. . . . and uranvl(l+) ,. ions (9,Sections 2.252 and 3.32). (In their original paper (5, p. 133) Ewens and Hassett stated thut "In \.iew of this unreriainty [of the existence of the U0z2+ cation], for the sake of uniformity with the other comwunds of the t". w e M-dL - .. etc., . . . and in deierenre 111c u . & n , we propose that the name uranyl be retain~.dfor compormds containing the UOz reridue.") Additional names in the 11970 ltules include: Isopolyanians Cr4013~-tetrachromate(2-) 0 0 0 5 SP-0-P-0-PO 1-thiotriphosphate(5-) (9, Section 0 0 0 4.15) ~
OP-0-P-0-PO 0 0 0 Heteropolyanions [03Cr-0-Se03]2[OAS(M~O&]~-
~~~~
1,2-dithiotriphosphate(5-) (9, Section
4.15) chromatoselenate(2-) (9, Section 4.211) tris(molyhdato)arsenate(3-) (9, Section
4.214) Condensed Heteropolyanions dodecawolframophosphate(3-) (9, [PW120m-~ Section 4.22) dodeeamolyhdocerate(IV)(8-) (9, [CelvMonOazlsSection 4.221 Nitriles K [ O S ~ ~ ~ ' ( N ) O ~ J potassium nitridotrioaoosmate(1-) (9, Section 5.35) Anionic Ligands -OOCCH(O-)CHtartrato(3-) (9, Section 7.314) (0H)COO-OOCCH(OH)CH- tartrato(2-) (9, Section 7.314) (0H)COOCyclopentadienyl Complexes [Fe(CsH5)2l[BFd ferrocene(l+)tetrafluoroborate(1-) (9,Section 7.43) Borane Ions IB(CHd2Hzldihydrodimethylhorate(1-) (9, Section 11.5) [B~oClddecachlorodecahorate(2-) (9, Section 11.5) triammineheptahydrodecahoron(l+) (9, [BloH~(NHs)sl+ Section 11.6) In some cases E-B numhers are used because they are more noncommittal than Stock numhers, e.g., pentacyanohydridocobaltate(3-) for [Co(CN)sH]3- rather than pentacya-
nohydridocobaltate(II1). Acknowledgment
The authors wish to thank W. Conard Fernelius and K. A. Volume 62
Number 6 June 1985
475
Jensen for valuable suggestions and information in the preparation of this article. Literature Cited I11 Kauffmsn,G.B.,snd J4rgensen.C. K., J.CHEM. EDUC.,62,243(1985). 12) Block, W. H., Jensen, K. A,, Jqrgensen. C. K., and Kauffman, G. B., Ambir, 28,171 (1981); J. Coord. Chem., 11,261 (1982): J. Chem. In/. Comp. Sci.,22, 125 (19821; Poivhedmn,2,111983); Kauffman,G. B.,Bmck, W. H., Jen8en.K. A.,and J4cgensen. C. K., .I. CHEMEDUC.,60.509 (1983). (3) 1. U. C. Kommision fur die Reform der Nomenclatur der anorganiachen Chemie,Ben. 7 3 4 5 3 (1940).S w a h Remy, H.,Die Chemie.55.267 (1942) for8 historid account of these rules. (4) (a) Jarissen. W. P., Bassett, H.,Damiens, A,, Fiehfer. F.. and Remy, H., J. Chem. Sm., 1404 (1940); ( h ) J Amer Chem. Sor., 63,889 (1941). (5) Ewens, R.V.G.,andBsssett,H.,ChemInd.. 131 11949). (6) Powe1l.H. M.,J. Chem.Soc.ZM9 (1950). 17) "Who's Who in British Science," Leanard Hill, London, 1953, p. 23. 181 Fora reviewofNO mmpleressep Moeller, T., J. CHEM.EDUC., 23,542 (1946): Mattern, J. A.. and Gill, S. J., in Bsilar, J. C., Jr. (Ed.), "The Chemistry of the Coordination Compounds," Reinhold PublishingCam.,NewYmk, 1956,Chap. 16:andKsuffman. G.B., Coord Chem. R s u , 11. 161 (19731, p. 177 and references cited therein. For
19) International union & P U ~and ~ p p ~ i e~ dh e i i s t r y , ' , , ~ o k e n & t u rofe ~norgsnic Chemistry, 1970," Bufterworths, London, 1971.
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tiated the trend reversing the pasitians of the numerals and signs. (11) International Unian of Pure and Applied Chemistry, "Nomenclature of Inorganic Chemiatry. 1957," Buttenvorths Scientific Publications, London, 1959 (in Freneh and English). Because of the color of its binding, this is !.nor"" asthe "Red Brnk" to distinguish it from theeorreqonding"B1ueBooY (Internstiand Union ofpure and Applied Chemirtry, Nomenclature of Organic Chemistry," Sections A and B, 2nd ed., Butterworths,London, 1966:Seetion C, Butterworths, London, 1965:Sections A. B, and C Combined.3rded.. Butterworths,London, 1971; Section8A.B. C, D, E,F,andG, Pe~gamonP-, Oxford, 1979.The Englishversion of the'TtedBook" wasteprinted in J. Amer. Cham. Sm.. 82,5623 (196Ql.Between the firstand second editions of the "Red Bwlr" the use of E-B notation increased hemendously. For example, it was adoptad for ligands by Chemical Ab8lrorfa ("Intraduction to Chemical Substances.Index," Chem. Abatr., 56.57 (1962)) and by the ACS Boron , 1151, 1441 119541, Patterson, A. Nomenclature Committee (Cham. Eng. N D ~ U I32 M.,Chem.Eng News.36 [6],560(1956); J. Cham.Doc.,6,95(1964):lnorg.Chem., 7.1945 (1968): Kirk, R. E.,snd Othmer. D.F.,"EneyclopedisofChemicdTechnolw,I)1st Supplementary Val., Interreienee, New Yark, 1957, pp. 105-104). 49,814 (1972) and (12) Fernellus, W. C., Loening,K., and Adams,R. M.,J. CHEM.EDUC., Fernelius, W.C.,J.CH~M.Eouc.,59,964 (1982). 113) Pure AODIChem . 2 5 4 1 i l 9 R l i ~
