Coordination compounds are formulated and named according to the IUPAC system.

Few rules for naming coordination compounds are:

(I) In ionic complex, the cation is named first and then the anion.

(II) In the coordination entity, the ligands are named first and then the central metal ion.

(III) When more than one type of ligands are present, they are named in alphabetical order of preference with any consideration of charge.

what is the IUPAC name of [Ni(CO)₄]?

tetracarbonylnickel(0)

In [Ni(CO)₄],

x + 4(0) = 0

x = 0

28Ni : [Ar]4s²3d⁸ 

Its IUPAC name is tertracarbonynickel(0)