Which ligand names have to be parenthesized while naming the Mononuclear Coordination entities

While studying about the ***Nomenclature of Coordination Compounds*** I came to know that



> 
> While writing formulae of **Mononuclear Coordination entities** polyatomic ligands are enclosed in parenthesis and also their abbreviations.
> 
> 
> 


But while naming the entities should I follow the same rule?


Like for $\ce{[Ni(H2O)2(en)2]SO4}$ should it be named as



> 
> Di(aqua)bis(ethylene-1,2-diamine)nickel(II) suphate
> 
> 
> 


Or



> 
> Diaquabis(ethylene-1,2-diamine)nickel(II) sulphate
> 
> 
> 


I Mean is there any rule that says you only need to close certain species of ligands like specifically bidentate (such as **en**) and polydented ligands (such as **EDTA**) and can keep the others as they are?


Thanks.




Greek prefixes are used to designate the number of each type of ligand in the complex ion, e.g. di-, tri- and tetra-. If the ligand already contains a Greek prefix (e.g. ethylenediamine) or if it is polydentate ligands (ie. can attach at more than one binding site) the prefixes bis-, tris-, tetrakis-, pentakis-, are used instead.


Bottom line - parenthesize only those ligands which already has a greek prefix in its name so that you can highlight the use of the alternative prefixes such as bis-,tris- etc.


Ps -Diaquabis(ethylene-1,2-diamine)nickel(II) sulphate is the correct naming but you can make it more appropriate by using ethane instead of ethylene


 2