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A D D I T I V E  N O M  E N C L A T U R E                           IR-7.4





                          For heterooligonuclear systems, more conventions are needed  t o  i dentify and name  t he
                       collection of central atoms, and to number the central atoms so as to provide locants for the
                       ligands.

                       Example:

                           5. Me 3 SiSeSiMe 3
                              m-selenido-bis(trimethylsilicon) (additive), or
                                          3
                                               3
                              hexamethyl-1k C,2k C-disiliconselenium(2 Si—Se) (additive), or
                              1,1,1,3,3,3-hexamethyldisilaselenane (substitutive)
                       Note that in the last example one can choose to name the compound as dinuclear or
                       trinuclear. The complexities  d eriving from the structural variations  w  hich may occur with
                       homonuclear and heteronuclear c entral atom clusters and bridging  g roups are dealt w  ith in
                       more detail in Sections IR-9.2.5.6 to IR-9.2.5.7.



           IR-7.4      I N O R G A N I C  C H A I N S  A N D  R I N G S


           IR-7.4.1    General
                       Inorganic  c hain and ring structures m  ay be named with no implications about the nature of
                       bonds, except  f or the connectivity of the molecule or ion, using a  p articular system of
                       additive n omenclature. The m  ethod can be applied to all chain and ring c ompounds although
                       it is principally intended for species composed mainly  o f  a toms other than carbon. While
                       small molecules can be named more conveniently  b y  u sing several alternative methods, t he
                       advantage of this nomenclature system lies in the simplicity with which complicated
                       structures  c an be derived from the name and vice versa. D  etails of this system are given  i n
                       Ref. 2; a  s implified treatment is provided here.
                          The overall topology of the structure is specified as follows. A  n  eutral chain
                       compound is called  ‘ catena’ p receded by a  m  ultiplicative prefix, ‘di’, ‘tri’, etc., to indicate
                       the number of branches in the molecule. Likewise, cyclic compounds are called ‘cycle’
                       preceded by the appropriate multiplicative prefix. A  m  ixed chain and ring  c ompound is
                       classified as an assembly composed of acyclic  a nd cyclic modules and, if neutral, is
                       named as ‘catenacycle’, with appropriate multiplicative prefixes inserted as in Example 3
                       below.

                       Examples:

                           1.








                                                           tricatena




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