Page 43 - Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005)

G R A M M A R I R-2.9

Example:
20. 1 +
AsPh
2 3 4
ON CO
Cr
MeCN NCMe
3 C 3
O
4
(OC-6-43)-bis(acetonitrile)dicarbonylnitrosyl(triphenylarsane)chromium(1þ)

IR-2.8.2 Roman numerals

Roman numerals are used in formulae as right superscripts to designate the formal oxidation
state.

Examples:

III
II
1. [Co Co W 12 O 42 ] 7
2. [Mn VII O 4 ]
II
3. Fe Fe III 2 O 4
In names they indicate t he formal oxidation state of an atom, and are enclosed in parentheses
immediately following the name of the atom being qualified.

Examples:

4. [Fe(H 2 O) 6 ] 2þ hexaaquairon(II)
5. [FeO 4 ] 2 tetraoxidoferrate(VI)

IR-2.9 I T A L I C L E T T E R S

Italic letters are used in names as follows.

(a) For geometrical and structural prefixes s uch as cis, c yclo, catena, t riangulo, nido, etc.
(see Table V).

(b) To designate s ymbols of central atoms in the bonding descriptor in polynuclear
compounds.
Example:

1. [Mn 2 (CO) 10 ] b is(pentacarbonylmanganese)(Mn—Mn)

(c) In double o xides a nd hydroxides w hen t he structural type is to be indicated.

Example:

2. MgTiO 3 (ilmenite type)

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