Page 4 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

P R E F A C E

problems a ssociated with the presence of p-bonded l igands. Chapter I R-9 is also
considerably changed ( cf. R ed Book I , C hapter 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 o f c entral atoms in names of
polynuclear compounds (Section IR-9.2.5.6); the bringing t ogether o f s ections on
configuration (Section IR-9.3) a nd their separation from those o n c onstitution (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 w ith guidance on how to choose between t hese
shapes a nd 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 A cids and Derivatives (Chapter IR-8), it
includes t he slightly revised concept of ‘hydrogen names’ in Section IR-8.4 (and some
traditional ‘ous’ and ‘ic’ n ames have been reinstated for consistency and because they are
required f or organic nomenclature purposes, i.e. i n t he new Blue Book).
The reader facing the problem of how to name a g iven compound or species may find
help in several ways. A fl owchart is provided in Section IR-1.5.3.5 which will in most cases
guide the user to a S ection or Chapter where rules can be found for generating at least one
possible n ame; a s econd flowchart is given in Section IR-9.2.1 to assist in the application of
additive n omenclature specifically to coordination and organometallic compounds. A more
detailed subject index i s a lso provided, as is an extended guide to possible alternative names
of a w ide range of simple inorganic compounds, i ons and radicals ( in Table IX).
For most compounds, f ormulae are another important type of compositional or structural
representation and for some c ompounds a f ormula i s p erhaps easier to construct. In Chapter
IR-4 (Formulae) several changes a re made in order to make t he presentation of a f ormula
and its corresponding name more c onsistent, e.g. the order of ligand citation ( which does not
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 f ormulae less c umbersome. T hus, recommendations for the
construction and use o f a bbreviations are provided in Section IR-4.4.4, with an extensive list
of established abbreviations given in Table VII (and with structural f ormulae for the ligands
given in Table VIII).
Two chapters o f R ed Book I have been shortened o r s ubsumed since in both areas
extensive revision is still necessary. First, the chapter on Solids (IR-11) now describes only
basic topics, more r ecent 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 I UPAC and IUCr will lead t o t he additional nomenclature required
for the rapidly e xpanding 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. t he separate, more comprehensive but dated,
chapter on boron nomenclature, I-11, in Red B ook I), within Chapter I R-6 (Parent Hydride
Names and Substitutive Nomenclature), while more advanced aspects are left for elaboration
in a f uture project.
Other changes include a s ection o n n ew elements and the procedure by which they are
now named (Section IR-3.1) a nd a s implified coverage of the systematic method for naming

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