Question

Write the IUPAC name of $[PtCl{(N{H_3})_2}(N{O_2})]$ .
A) Platinum diaminechloronitrite
B) chloronitrile-IN-diammineplatinum (II)
C) diammine dichloride nitrito-N-platinum (II)
D) diamminechloronitrito-N-platinate (II)

Answer 1

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 solution
Ligands can be defined as the entities which can donate electron pairs to the metal atom attached to it. For e.g. amino group ( $- N{H_3}$ ), chloride group ( $- Cl$ ). There are three types of ligands. Neutral ligands can be defined as the ligands which do not have any charge, for example $- N{H_3}$ . Anionic ligands are those in which the ligands have negative oxidation state, for example $- Cl$ , $N{O_2}$ 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, $[PtCl{(N{H_3})_2}(N{O_2})]$
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 the name of the complex ion, we always have to follow the alphabetical order. Names can be seen in the books.
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 $N{H_2}C{H_2}C{H_2}N{H_2}$ , ethylenediamine which is represented as, $N{H_3}$ is. $N{O_2}$ Written as nitrito-N and $ONO$ can be written as nitrito-O.
D) The name of the central metal atom is written 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 –
$\begin{gathered} x + ( - 1) + 2 \times 0 + ( - 1) = 0 \\\ \Rightarrow x - 2 = 0 \\\ \Rightarrow x = + 2 \\\ \end{gathered}$
Hence the IUPAC name of $[PtCl{(N{H_3})_2}(N{O_2})]$ can be written as diamminechloridonitrito-N-platinum (II).
The correct option is (C).

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.