Page 14 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

IR-1.5 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

There are several accepted s ystems f or the construction of names, as discussed in
Section IR-1.5.3. Perhaps the simplest is that used for naming binary substances. This set
of rules leads to a n ame such as iron dichloride for the substance F eCl 2 ; t his name
involves the juxtaposition of element names (iron, chlorine), their ordering i n a specific
way (electropositive before electronegative), the modification of an element name to
indicate charge (the ‘ide’ ending designates an elementary anion and, more generally, an
element being t reated formally a s a n a nion), and the use of the multiplicative prefix ‘di’ to
indicate composition.
Whatever t he pattern o f n omenclature, names are constructed from entities such as:

element name r oots,
multiplicative p refixes,
prefixes indicating a toms or groups either substituents or ligands,
suffixes indicating c harge,
names and endings denoting parent compounds,
suffixes indicating c haracteristic substituent groups,
infixes,
locants,
descriptors ( structural, geometric, spatial, etc.),
punctuation.

IR-1.5.3 Systems of nomenclature

IR-1.5.3.1 General

In the development of nomenclature, several systems h ave emerged f or the construction of
chemical names; each system has its own inherent logic and set of rules (grammar). Some
systems a re broadly applicable whereas p ractice has led to the use of specialized systems i n
particular a reas of chemistry. The existence of several distinct nomenclature systems leads
to logically consistent alternative names for a g iven substance. Although this flexibility
is useful in some contexts, the excessive proliferation of alternatives can hamper
communication and even impede trade and legislation procedures. Confusion can also
occur when the grammar of one nomenclature system is mistakenly used in another, leading
to names that do not represent any given system.
Three systems a re of primary importance i n i norganic chemistry, n amely compositional,
substitutive and additive nomenclature; they are described in more detail in Chapters IR-5,
IR-6 and IR-7, respectively. Additive nomenclature is perhaps the most g enerally applicable
in inorganic c hemistry, but substitutive nomenclature may be applied in appropriate areas.
These two systems require knowledge of the constitution (connectivity) of the compound or
species being named. If only the stoichiometry or composition of a c ompound is known o r t o
be communicated, compositional nomenclature is used.

IR-1.5.3.2 Compositional nomenclature

This term is used in the present recommendations to denote name constructions which are
based solely on the composition of the substances or species being n amed, as opposed to

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