Coordination Compounds 1 Question 1
####1. The coordination numbers of $Co$ and $Al$ in $\left[CoCl(en) _2\right] Cl$ and $K _3\left[Al\left(C _2 O _4\right) _3\right]$, respectively, are (en = ethane-1, 2-diamine)
(a) 5 and 3
(b) 3 and 3
(c) 6 and 6
(d) 5 and 6
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Answer:
Correct Answer: 1. (d)
Solution:
- Key Idea The total number of ligands to which the metal is directly attached is called coordination number.
The coordination numbers of $Co$ and $Al$ in $\left[Co(Cl)(en) _2\right] Cl$ and $K _3\left[Al\left(C _2 O _4\right) _3\right]$ are 5 and 6 respectively.
In first complex, ’en’ is a didentate ligand and ’ $Cl$ ’ is a unidentate ligand.
$\left[Co(Cl)(en) _2\right] Cl$, coordination number $=1+2 \times 2=1+4 \Rightarrow 5$
So, the coordination number is 5 .
For $K _3\left[Al\left(C _2 O _4\right) _3\right.$ b ’ $C _2 O _4^{2-}$, is a didentate ligand.
Coordination number $=3 \times 2=6$.
Hence, coordination number is 6 .
