Question

A complex whose IUPAC name is not correctly written is :

• A. $Fe(\sigma -C_5{H}_5{)}_2$, Bis(${\eta }^5$-cyclopentadienyl)iron(0)
• B. $Cr(C_6{H}_6{)}_2$, Bis(${\eta }^5$-benzene)chromium(0)
• C. $\left[CoC{l}_2\right(H_{2}O{)}_4]Cl.2H_{2}O$, Tetraaquadichlorocobalt(III)chloride-2-water
• D. $\left[Zn\right(NCS{)}_4{]}^{2-}$, Tetrathiocyanato-N-zincate(II)ion

Answer 1

The correct option is A $Fe(\sigma -C_5{H}_5{)}_2$, Bis(${\eta }^5$-cyclopentadienyl)iron(0)

The IUPAC name of the complex $Fe(\sigma -C_5{H}_5{)}_2$ is Bis(${\eta }^1$-cyclopentadienyl)iron(0) and not Bis(${\eta }^5$-cyclopentadienyl)iron(0).
this is because the ligand is attached to metal through sigma bond only. Thus option A is incorrectly named.
The IUPAC name of the complex $Cr(C_6{H}_6{)}_2$ is Bis(${\eta }^5$-benzene)chromium(0). In this complex, the ligand is attached to metal ion through pi bonds.
Thus option B is correctly named.
The IUPAC name of the compound $\left[CoC{l}_2\right(H_{2}O{)}_4]Cl.2H_{2}O$ is tetraaquadichlorocobalt(III)chloride-2-water.
The prefix tetra indicates four ligands and the prefix di indicates two ligands. The ligands are named in alphabetical order.
Thus option C is correctly named.
The IUPAC name of the complex $\left[Zn\right(NCS{)}_4{]}^{2-}$ is tetrathiocyanato-N-zincate(II)ion.
Here N represents the linkage through N atom of thiocyanato group.The prefix tetra indicates four ligands. For complex anion, the name of the zinc is written as zincate.
Thus option D is correctly named