Page 12 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

IR-1.3 G E N E R A L A I M S , F U N C T I O N S A N D M E T H O D S

to a g iven c lass. Each name m ight have value i n a specific situation, or be preferred by some
users, but there was then the possibility of confusion.
The need for uniform practice among English-speaking chemists was recognized as
early as 1886 and resulted in agreements on usage by the British and American Chemical
Societies. In 1913, the Council of the International Association of Chemical S ocieties
appointed a commission of inorganic a nd organic nomenclature, but World War I a bruptly
ended its activities. Work was resumed in 1921 when IUPAC, at its second conference,
appointed c ommissions on the nomenclature of inorganic, organic, and biological chemistry.
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The first comprehensive report of the inorganic c ommission, in 1940, had a m ajor effect
on the systematization of inorganic nomenclature and made many chemists aware of the
necessity for developing a m ore fully systematic nomenclature. Among the significant
features of this initial report were the adoption of the Stock system for indicating o xidation
states, the establishment o f o rders f or citing constituents of binary compounds in formulae
and in names, the discouragement of the use of bicarbonate, etc. i n t he names of acid s alts,
and the development of uniform practices for naming addition c ompounds.
These IUPAC recommendations were then revised and issued as a s mall book in 1959 8
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followed by a s econd r evision in 1971 and a s upplement, entitled How to Name an
Inorganic Substance, i n 1 977. 10 In 1990 the IUPAC recommendations were again fully
revised 11 in order to bring together t he many and varied changes w hich had occurred in the
previous 20 years.
More specialized areas have also been considered, concerning polyanions, 12 metal
complexes of tetrapyrroles (based on Ref. 13), inorganic chain and ring compounds, 14 and
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graphite intercalation compounds. These topics, together with revised versions of papers o n
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isotopically modified inorganic compounds, hydrides of nitrogen a nd derived cations, anions
and ligands, 17 and regular single-strand and quasi single-strand inorganic and coordination
polymers, 18 comprise the seven chapters o f Nomenclature of Inorganic Chemistry II,
IUPAC R ecommendations 2000. 19 A p aper entitled Nomenclature of Organometallic
Compounds of the Transition E lements 20 forms the basis for Chapter I R-10 of this book.

IR-1.3 A I M S O F C H E M I C A L N O M E N C L A T U R E

The primary aim of chemical nomenclature is to provide methodology for assigning
descriptors (names and formulae) to chemical species so that they can be identified without
ambiguity, thereby facilitating communication. A s ubsidiary aim is to achieve standardiza-
tion. Although this need not be so absolute as to require only one name for a s ubstance, the
number of ‘acceptable’ names needs to be minimized.
When developing a s ystem of nomenclature, public needs and common usage must also
be borne in mind. In some c ases, the only requirement may be to identify a s ubstance,
essentially the requirement prior to the late 18th century. Thus, local n ames and
abbreviations are still used by small groups of specialists. Such local n ames suffice as
long as the specialists understand the devices used for identification. However, this is not
nomenclature as defined above since local names do not necessarily convey structural and
compositional information to a w ider audience. To be widely useful, a n omenclature system
must be recognisable, unambiguous, and general; the unnecessary use of local n ames and
abbreviations in formal scientific language should t herefore be discouraged.

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