NOMENCLATURE OF INORGANIC CHEMISTRY IUPAC Recommendations 2005 18 2 He 10 Ne 18 Ar 36 Kr 54 Xe 86 Rn 118 Uuo 17 9 F 17 Cl 35 Br 53 I 85 At 117 Uus 71 Lu 103 Lr 16 8 O 16 S 34 Se 52 Te 84 Po 116 Uuh 70 Yb 102 No 15 7 N 15 P 33 As 51 Sb 83 Bi 115 Uup 69 Tm 101 Md 14 6 C 14 Si 32 Ge 50 Sn 82 Pb 114 Uuq 68 Er 100 Fm 13 5 B 13 Al 31 Ga 49 In 81 Tl 113 Uut 67 Ho 99 Es s ment 12 30 Zn 48 Cd 80 Hg 112 Uub 66 Dy 98 Cf e El 11 29 Cu 47 Ag 79 Au 111 Rg 65 Tb 97 Bk e h oft 10 28 Ni 46 Pd 78 Pt 110 Ds 64 Gd 96 Cm e abl 9 27 Co 45 Rh 77 Ir 109 Mt 63 Eu 95 Am T dic 8 26 Fe 44 Ru 76 Os 108 Hs 62 Sm 94 Pu o i Per 7 25 Mn 43 Tc 75 Re 107 Bh 61 Pm 93 Np C PA 6 24 Cr 42 Mo 74 W 106 Sg 60 Nd 92 U U I 5 23 V 41 Nb 73 Ta 105 Db 59 Pr 91 Pa 4 22 Ti 40 Zr 72 Hf 104 Rf 58 Ce 90 Th 3 21 Sc 39 Y *57−71 lanthanoids ‡89−103 actinoids *57 La ‡89 Ac 2 4 Be 12 Mg 20 Ca 38 Sr 56 Ba 88 Ra 1 1 H 3 Li 11 Na 19 K 37 Rb 55 Cs 87 Fr International Union of Pure and Applied Chemistry Nomenclature of Inorganic Chemistry IUPAC RECOMMENDATIONS 2005 Issued by the Division of Chemical Nomenclature and Structure Representation in collaboration with the Division of Inorganic Chemistry Prepared for publication by Neil G. Connelly Ture Damhus University of Bristol, UK Novozymes A/S, Denmark Richard M. Hartshorn Alan T. Hutton University of Canterbury, New Zealand University of Cape Town, South Africa Coverimages#MurrayRobertson/visualelements1998–99,takenfromthe109VisualElementsPeriodicTable, availableatwww.chemsoc.org/viselements ISBN0-85404-438-8 AcataloguerecordforthisbookisavailablefromtheBritishLibrary #InternationalUnionofPureandAppliedChemistry,2005 Allrightsreserved Apartfromfairdealingforthepurposesofresearchfornon-commercialpurposesorforprivatestudy,criticismor review,aspermittedundertheCopyright,DesignsandPatentsAct1988andtheCopyrightandRelatedRights Regulations2003,thispublicationmaynotbereproduced,storedortransmitted,inanyformorbyanymeans, withoutthepriorpermissioninwritingofTheRoyalSocietyofChemistry,orinthecaseofreproductionin accordancewiththetermsoflicencesissuedbytheCopyrightLicensingAgencyintheUK,orinaccordancewith thetermsofthelicencesissuedbytheappropriateReproductionRightsOrganizationoutsidetheUK.Enquiries concerningreproductionoutsidethetermsstatedhereshouldbesenttoTheRoyalSocietyofChemistryatthe addressprintedonthispage. PublishedfortheInternationalUnionofPureandAppliedChemistrybyTheRoyalSocietyofChemistry, ThomasGrahamHouse,SciencePark,MiltonRoad,CambridgeCB40WF,UK RegisteredCharityNumber207890 Forfurtherinformationseeourwebsiteatwww.rsc.organdtheIUPACsiteatwww.iupac.org TypesetbyAldenBookset,Northampton,UK PrintedbyBiddlesLtd,King’sLynn,Norfolk,UK Preface Chemical nomenclature must evolve to reflect the needs of the community that makes use of it. In particular, nomenclature must be created to describe new compounds or classes of compounds; modified to resolve ambiguities which might arise; or clarified where there is confusionoverthewayinwhichnomenclatureshouldbeused.Thereisalsoaneedtomake nomenclature as systematic and uncomplicated as possible in order to assist less familiar users (for example, because they are only in the process of studying chemistry or are non- chemistswhoneedtodealwithchemicalsatworkorathome).ArevisionofNomenclature of Inorganic Chemistry, IUPAC Recommendations 1990 (Red Book I) was therefore initiated in 1998, under the guidance of the IUPAC Commission on Nomenclature of Inorganic Chemistry (CNIC) and then, on the abolition of CNIC in 2001 as part of the general restructuring of IUPAC, by a project group working under the auspices of the Division of Chemical Nomenclature and Structure Representation (Division VIII). The need to ensure that inorganic and organic nomenclature systems are, as far as possible,consistenthasresulted inextensivecooperationbetweentheeditorsoftherevised RedBookandtheeditorsofNomenclatureofOrganicChemistry,IUPACRecommendations (the revised ‘Blue Book’, in preparation). At present, the concept of preferred IUPAC names(PINs),animportantelementintherevisionoftheBlueBook,hasnotbeenextended toinorganicnomenclature(thoughpreferrednamesareusedhereinfororganic,i.e.carbon- containing, compounds when appropriate). Aplanned future project oninorganicPINswill need to face the problem of choice between the equally valid nomenclature systems currently in use. The present book supersedes not only Red Book I but also, where appropriate, Nomenclature of Inorganic Chemistry II, IUPAC Recommendations 2000 (Red Book II). OneofthemainchangesfromRedBookIisthedifferentorganizationofmaterial,adopted to improve clarity. Thus, Chapters IR-5 (Compositional Nomenclature, and Overview of NamesofIonsandRadicals),IR-6(ParentHydrideNamesandSubstitutiveNomenclature), and IR-7 (Additive Nomenclature) deal with the general characteristics of the three main nomenclaturesystemsappliedtoinorganiccompounds.(Notethatthenotation‘IR-’isused to distinguish chapters and sections in the current book from those in Red Book I, prefixed ‘I-’). The next three chapters deal with their application, particularly that of additive nomenclature,tothreelargeclassesofcompounds:inorganicacidsandderivatives(Chapter IR-8), coordination compounds (Chapter IR-9) and organometallic compounds (Chapter IR-10). Overall, the emphasis on additive nomenclature (generalized from the classical nomenclature of coordination compounds) which was already apparent in Red Book I is reinforced here. Examples are even included of organic compounds, from the borderline betweeninorganicandorganicchemistry,whichmaybeconvenientlynamedusingadditive nomenclature (although their PINs will be different). One important addition in this book is Chapter IR-10 on Organometallic Compounds. The separation of this material from that on Coordination Compounds (Chapter IR-9) reflects the huge growth in importance of organometallic chemistry and the very different v PREFACE problems associated with the presence of p-bonded ligands. Chapter IR-9 is also considerably changed (cf. Red Book I, Chapter I-10). This revised chapter includes a clarification of the use of the Z and k conventions in coordination and organometallic compounds (Section IR-9.2.4.3); new rules for the ordering of central atoms in names of polynuclear compounds (Section IR-9.2.5.6); the bringing together of sections on configuration (Section IR-9.3) and their separation from those on constitution (Section IR-9.2); and the addition of polyhedral symbols for T-shaped (Section IR-9.3.3.7) and see- saw (Section IR-9.3.3.8) molecules, along with guidance on how to choose between these shapes and those of closely related structures (Section IR-9.3.2.2). The chapter on Oxoacids and Derived Anions (Red Book I, Chapter I-9) has also been extensively modified. Now called Inorganic Acids and Derivatives (Chapter IR-8), it includes the slightly revised concept of ‘hydrogen names’ in Section IR-8.4 (and some traditional ‘ous’ and ‘ic’ names have been reinstated for consistency and because they are required for organic nomenclature purposes, i.e. in the new Blue Book). The reader facing the problem of how to name a given compound or species may find helpinseveralways.AflowchartisprovidedinSectionIR-1.5.3.5whichwillinmostcases guide the user to a Section or Chapter where rules can be found for generating at least one possiblename;asecondflowchartisgiveninSectionIR-9.2.1toassistintheapplicationof additive nomenclature specifically to coordination and organometallic compounds. A more detailedsubjectindexisalsoprovided,asisanextendedguidetopossiblealternativenames of a wide range of simple inorganic compounds, ions and radicals (in Table IX). Formostcompounds,formulaeareanotherimportanttypeofcompositionalorstructural representationandforsomecompoundsaformulaisperhapseasiertoconstruct.InChapter IR-4 (Formulae) several changes are made in order to make the presentation of a formula anditscorrespondingnamemoreconsistent,e.g.theorderofligandcitation(whichdoesnot now depend on the charge on the ligand) (Section IR-4.4.3.2) and the order and use of enclosing marks (simplified and more consistent with the usage proposed for the nomenclature of organic compounds) (Section IR-4.2.3). In addition, the use of ligand abbreviations can make formulae less cumbersome. Thus, recommendations for the constructionanduseofabbreviationsareprovidedinSectionIR-4.4.4,withanextensivelist ofestablishedabbreviationsgiveninTableVII(andwithstructuralformulaefortheligands given in Table VIII). Two chapters of Red Book I have been shortened or subsumed since in both areas extensiverevision isstillnecessary. First,thechapteronSolids(IR-11)nowdescribesonly basic topics, more recent developments in this area tending to be covered by publications from the International Union of Crystallography (IUCr). It is to be hoped that future cooperation between IUPAC and IUCr will lead to the additional nomenclature required for the rapidly expanding field of solid-state chemistry. Second, boron chemistry, particularly that of polynuclear compounds, has also seen extensive development. Again, therefore, only the basics of the nomenclature of boron- containing compounds are covered here (cf. the separate, more comprehensive but dated, chapter on boron nomenclature, I-11, in Red Book I), within Chapter IR-6 (Parent Hydride NamesandSubstitutiveNomenclature),whilemoreadvancedaspectsareleftforelaboration in a future project. Other changes include a section on new elements and the procedure by which they are nownamed(SectionIR-3.1)andasimplifiedcoverageofthesystematicmethodfornaming vi PREFACE chains and rings (adapted from Chapter II-5 of Red Book II). Lesser omissions include the section on single strand polymers (now updated as Chapter II-7 in Red Book II) and the several different outdated versions of the periodic table. (That on the inside front cover is the current IUPAC-agreed version.) Some new recommendations representbreakswith tradition,in the interest ofincreased clarity and consistency. For example, the application of the ending ‘ido’ to all anionic ligands with ‘ide’ names in additive nomenclature (e.g. chlorido and cyanido instead of chloro and cyano, and hydrido throughout, i.e. no exception in boron nomenclature) is part of a general move to a more systematic approach. Acknowledgements It is important to remember that the current volume has evolved from past versions of the RedBookanditisthereforeappropriatefirsttoacknowledgetheeffortsofpreviouseditors andcontributors.However,wewouldalsoliketothankthemanypeoplewithoutwhosehelp thisrevisionwouldnothavecometofruition.MembersofCNICwereinvolvedintheearly stages of the revision (including Stanley Kirschner who began the task of compiling ligand abbreviations and what has become Tables VII and VIII), and members of the IUPAC Division VIII Advisory Subcommittee (particularly Jonathan Brecher, Piroska Fodor- Csa´nyi, Risto Laitinen, Jeff Leigh and Alan McNaught) and the editors of the revised Blue Book(WarrenPowellandHenriFavre)havemadeextremelyvaluablecomments.However, the bulk of the work has been carried out by a project group comprising the two Senior Editors, Richard Hartshorn and Alan Hutton. NEIL G. CONNELLY and TURE DAMHUS (Senior Editors) vii Contents IR-1 GENERAL AIMS, FUNCTIONS AND METHODS OF CHEMICAL NOMENCLATURE 1 IR-1.1 Introduction 1 IR-1.2 History of chemical nomenclature 2 IR-1.3 Aims of chemical nomenclature 3 IR-1.4 Functions of chemical nomenclature 4 IR-1.5 Methods of inorganic nomenclature 4 IR-1.6 Changes to previous IUPAC recommendations 8 IR-1.7 Nomenclature recommendations in other areas of chemistry 13 IR-1.8 References 13 IR-2 GRAMMAR 15 IR-2.1 Introduction 16 IR-2.2 Enclosing marks 17 IR-2.3 Hyphens, plus and minus signs, ‘em’ dashes and bond indicators 24 IR-2.4 Solidus 27 IR-2.5 Dots, colons, commas and semicolons 27 IR-2.6 Spaces 30 IR-2.7 Elisions 31 IR-2.8 Numerals 31 IR-2.9 Italic letters 34 IR-2.10 Greek alphabet 35 IR-2.11 Asterisks 36 IR-2.12 Primes 36 IR-2.13 Multiplicative prefixes 37 IR-2.14 Locants 38 IR-2.15 Ordering principles 40 IR-2.16 Final remarks 44 IR-2.17 References 45 IR-3 ELEMENTS 46 IR-3.1 Names and symbols of atoms 46 IR-3.2 Indication of mass, charge and atomic number using indexes (subscripts and superscripts) 47 ix CONTENTS IR-3.3 Isotopes 48 IR-3.4 Elements (or elementary substances) 48 IR-3.5 Elements in the periodic table 51 IR-3.6 References 52 IR-4 FORMULAE 53 IR-4.1 Introduction 54 IR-4.2 Definitions of types offormula 54 IR-4.3 Indication of ionic charge 57 IR-4.4 Sequence of citation of symbols in formulae 58 IR-4.5 Isotopically modified compounds 64 IR-4.6 Optional modifiers offormulae 65 IR-4.7 References 67 IR-5 COMPOSITIONAL NOMENCLATURE, AND OVERVIEW OF NAMES OF IONS AND RADICALS 68 IR-5.1 Introduction 68 IR-5.2 Stoichiometric names of elements and binary compounds 69 IR-5.3 Names of ions and radicals 70 IR-5.4 Generalized stoichiometric names 75 IR-5.5 Names of (formal) addition compounds 80 IR-5.6 Summary 81 IR-5.7 References 82 IR-6 PARENT HYDRIDE NAMES AND SUBSTITUTIVE NOMENCLATURE 83 IR-6.1 Introduction 84 IR-6.2 Parent hydride names 84 IR-6.3 Substitutive names of derivatives of parent hydrides 101 IR-6.4 Names of ions and radicals derived from parent hydrides 105 IR-6.5 References 110 IR-7 ADDITIVE NOMENCLATURE 111 IR-7.1 Introduction 111 IR-7.2 Mononuclear entities 113 IR-7.3 Polynuclear entities 114 IR-7.4 Inorganic chains and rings 118 IR-7.5 References 123 x