Page 17 - 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-1.6

Examples:

1. NO 2
Would you like simply to specify a c ompound with this empirical formula, or a
compound with this molecular formula? Would y ou like to stress that it is a
radical? Would you like to specify the connectivity ONO?
:
2. Al 2 (SO 4 ) 3 12H 2 O
Would you like simply to indicate that this is a c ompound composed of
dialuminium trisulfate and water in the proportion 1 :12, or would you like to
specify explicitly that it contains hexaaquaaluminium(3þ) i ons?
3
3. H 2 P 3 O 10
Would you like to specify that this is triphosphoric acid (as defined in Table IR-8.1)
from which three hydrogen(1þ) i ons have been removed? W ould you like to
specify from where they have been removed?

The flowchart shown i n F igure I R-1.1 (see page 9) proposes general guidelines for naming
compounds and other species.

IR-1.6 C H A N G E S T O P R E V I O U S I U P A C R E C O M M E N D A T I O N S

This section h ighlights significant changes made i n t he present recommendations relative
to earlier IUPAC nomenclature publications. In general, t hese changes have been introduced
to provide a m ore l ogical and consistent nomenclature, aligned with that of Nomenclature of
Organic Chemistry, IUPAC Recommendations, R oyal Society of Chemistry, in preparation
(Ref. 21), as far as possible.

IR-1.6.1 Names of cations

Certain cations derived from parent hydrides were given names in Refs. 11 and 19 which
appear t o b e s ubstitutive but which do not follow the rules of substitutive nomenclature. For
example, according t o R efs. 11 and 19, N 2 H 6 2þ may be named hydrazinium(2þ). However,
the ending ‘ium’ in itself denotes addition of hydrogen(1þ) a nd thus implies the charge.
Consequently this cation is named hydrazinediium or diazanediium, with no charge number,
both in Section IR-6.4.1 and in Ref. 21.

IR-1.6.2 Names of anions

When constructing systematic names for anions, consistency is achieved by adhering
without exception to the following rules:
(i) Compositional names of homopolyatomic anions end in ‘ide’.

Examples:
1. I 3 , t riiodide(1 )

2
2. O 2 , d ioxide(2 )
(ii) Parent hydride-based names of anions based on the formal removal of hydrogen(1þ)
end in ‘ide’.

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