Page 80 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

IR-5.3 C O M P O S I T I O N A L N O M E N C L A T U R E

3. Cu þ copper(1þ)
4. Cu 2þ copper(2þ)
5. I þ iodine(1þ)
6. H þ hydrogen(1þ), hydron
1
7. H þ protium(1þ), proton
2
8. H þ deuterium(1þ), deuteron
3
9. H þ tritium(1þ), triton
10. He * þ helium( * 1þ)
11. O * þ oxygen( * 1þ)
(2 *)2þ
12. N 2 dinitrogen(2 * 2þ)

The names of the hydrogen isotopes a re discussed in Section IR-3.3.2.

IR-5.3.2.3 Homopolyatomic cations
Homopolyatomic cations are named by adding the charge number to the stoichiometric
name of the corresponding neutral species, i.e. the element name with the appropriate
multiplicative prefix. Radical dots may be added to indicate t he presence of unpaired
electrons.

Examples:
þ * þ
1. O 2 or O 2 dioxygen(1þ) o r d ioxygen( * 1þ)
2þ
2. S 4 tetrasulfur(2þ)
2þ
3. Hg 2 dimercury(2þ)
4þ pentabismuth(4þ)
4. Bi 5
þ
5. H 3 trihydrogen(1þ)
IR-5.3.2.4 Heteropolyatomic cations

Heteropolyatomic c ations are usually named either substitutively (see Section IR-6.4) or
additively ( see Chapter IR-7). Substitutive names do not require a c harge number, because
the name itself i mplies the charge (Examples 2 a nd 4 b elow). Radical dots may be added to
additive names to indicate the presence of unpaired electrons.
A f ew cations have established and still acceptable non-systematic names.

Examples:
þ
1. NH 4 azanium (substitutive), or ammonium (acceptable non-systematic)
2. H 3 O þ oxidanium (substitutive), or oxonium (acceptable non-systematic;
not hydronium)
þ
3. PH 4 phosphanium (substitutive)
4. H 4 O 2þ oxidanediium (substitutive)

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