Question
Question: Write the IUPAC name \( [PtC{l_2}{(N{H_3})_2}] \) ....
Write the IUPAC name [PtCl2(NH3)2] .
Solution
Coordination number can be defined as the number which is used to detect the surrounding ligands around a central metal atom in a coordination compound. For example, in the above complex the coordination number is four.
Complete step by step solution:
Ligands can be defined as the entities which can donate electron pair to the metal atom attached to it. For e.g. amino group ( −NH3 ), chloride group ( −Cl ). There three types of ligands. Neutral ligands can be defined as the ligands which donot have any charge, for example −NH3 . Anionic ligands are those in which the ligands have negative oxidation state, for example −Cl . Cationic ligands are those in which the ligands have positive oxidation state, for example −NO .
Coordination compounds are those where a central metal atom is present along with the ligands in the coordination sphere. For example, [PtCl2(NH3)2] .
The naming of coordination complexes can be written by following the rules-
A) In the name of complex the name of cations are always prior to anions. Like the way in ionic compounds.
B) In name of the complex ion, always we have to follow the alphabetical order.
C) The common ligands can be represented as, for anionic ligands their name ends with "-o", for neutral ligands, the name of the molecule is NH2CH2CH2NH2 , ethylenediamine which is represented as, NH3 is.
D) The name of central metal atom is written in last in continuation with oxidation number in brackets in roman.
The oxidation state of platinum from complex (say for example x) can be calculated as –
x+2×(−1)+2×0=0 ⇒x−2=0 ⇒x=+2
Hence the IUPAC name of [PtCl2(NH3)2] can be written as diamminedichloridoplatinum (II).
Note:
Platinum belongs to the transition metal series. It mainly forms square planar complexes as moving down the nickel group (10th group) the tendency of formation of square planar complexes increases in a transition metal group.