Question

The correct IUPAC name of $\left[ {Pt{{\left( {N{H_3}} \right)}_2}C{l_2}} \right]$ is,
A. Diamminedichloroplatinum(II)
B. Diamminedichloroplatinum(IV)
C. Diamminedichloroplatinum(0)
D. Dichloro,diamine platinum(IV)

Answer 1

The given compound is a coordination compound. IUPAC has proposed certain rules for the nomenclature of coordination compounds. Following these rules we can name all the coordination complexes.

Complete step by step answer:
The coordination compounds are named following the principles of additive nomenclature. The ligands around the central atom are identified in the name and listed as prefixes to the name of the central atom. The IUPAC rules for nomenclature of coordination compounds are,
1.The cation is named first.
2.Ligands are named in alphabetical order before the name of the central atom.
3.Named of anionic ligands end with –o. Names of cationic and neutral ligands are written as such.
4.Number of ligands are indicated using prefixes mono, di, tri etc. If the name of ligands itself contains numerical prefixes, then the terms bis, tris, tetrakis etc are used.
5.Oxidation number of metal ions is indicated by Roman numbers in parenthesis.
6.If the complex ion is cation, the name of metal is written as such. If the complex ion is anion, the name of metal ends with the suffix –ate.
7.Neutral complex molecules are named similar to that of the complex cation.
Now let us name the given compound $\left[ {Pt{{\left( {N{H_3}} \right)}_2}C{l_2}} \right]$. This is a neutral complex. Hence it can be named similar to that of complex cation. Central metal is Platinum. It contains two types of ligands- $N{H_3}$ and $C{l^ - }$. The name of the ligand $N{H_3}$ is ammine. It is a neutral ligand. Since two amine ligands are present, prefix di- should be used. The name of $C{l^ - }$ ligand is chloride. It is an anionic ligand. Hence it will be written as chloro. Since two chloride molecules are present, prefix di- should be used. Now we need to calculate the oxidation state of metal. The only charged ligand is $C{l^ - }$, with one negative charge. Hence charge on Pt will be $+ 2$ (since two $C{l^ - }$ ligands are present). The ligand name ammine will come first as the ligand names are written in alphabetical order.
Hence name of the given compound is,
Diamminedichloroplatinum(ll).

So, the correct answer is Option A.

Note: There should be no space between the names of ligands or between names of ligands and central metal. Space should be given only to separate anionic and cationic parts. This is a common mistake happening while writing names of coordination compounds.