Page 15 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

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 I R-1.5

systems i nvolving structural information. One such construction is that of a g eneralized
stoichiometric name. T he names of components w hich may themselves b e e lements or
composite entities ( such a s p olyatomic i ons) a re listed with multiplicative prefixes giving the
overall stoichiometry of the compound. If there are two or more components, they are
formally d ivided into two classes, t he electropositive and the electronegative components.
In this respect, the names are like traditional salt n ames although there is no implication
about the chemical nature of the species being named.
Grammatical rules are then required to specify the ordering of components, the use of
multiplicative prefixes, and the proper endings for the names of the electronegative
components.

Examples:

1. trioxygen, O 3
2. sodium chloride, NaCl
3. phosphorus trichloride, PCl 3
4. trisodium pentabismuthide, Na 3 Bi 5
5. magnesium chloride hydroxide, MgCl(OH)
6. sodium cyanide, NaCN
7. ammonium chloride, NH 4 Cl
8. sodium acetate, NaO 2 CMe

IR-1.5.3.3 Substitutive nomenclature
Substitutive nomenclature is used extensively f or organic compounds and is based on the
concept of a p arent hydride modified by substitution of hydrogen atoms by atoms and/or
groups. 21 (In particular i t i s u sed for naming organic ligands in the nomenclature of
coordination and organometallic compounds, e ven though t his is an overall additive
system.)
It is also used for naming compounds formally d erived from the hydrides of certain
elements in groups 13–17 of the periodic table. Like carbon, these elements form chains and
rings which can have many d erivatives, and the system avoids the necessity for specifying
the location of the hydrogen atoms of the parent hydride.
Rules are required to name parent compounds and substituents, to provide an order of
citation o f s ubstituent n ames, and to specify the positions of attachment of substituents.

Examples:

1. 1,1-difluorotrisilane, SiH 3 SiH 2 SiHF 2
2. trichlorophosphane, PCl 3

Operations in which certain non-hydrogen atoms of parents are replaced b y d ifferent atoms
or groups, e.g. the skeletal replacements leading to ‘a’ names in organic chemistry (see
Sections P-13.2 and P-51.3 of Ref. 21), are usually considered as part of substitutive
nomenclature and are also used in certain p arts of inorganic c hemistry.

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