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

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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