Question

Which of the following is not a neutral ligand?
(A) ${H_2}O$
(B) $N{H_3}$
(C) $ONO$
(D) $CO$

Answer 1

In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding with the metal atom during the formation of complex generally involves formal donation of one or more the ligand’s electron pairs.

Complete answer:
The ions or molecules bound to the central atom/ion in the coordination entity called Ligands.
Neutral ligand is defined as the ligand which has neither positive nor negative charge.
(A) ${H_2}O$ is neutrally charged ligand
(B) $N{H_3}$ is neutral ligand
(C) $ON{O^ - }$ has charge on it, so it is not a neutral ligand.
(D) $CO$ is also neutral ligand.
When a ligand is bound to metal ion through a single donor atom as with $C{l^ - },{H_2}O\;{\text{or}}\;N{H_3};$ the ligand is called as uni dentate ligand.
When a ligand can bind through two donor atoms, the ligand is Bidenate
When a several donor atoms are present in a singa ligand called polydentate ligand
According to the above statement, the correct answer is (C).

Additional Information: Chelate ligand is said to be when a di or polydentate ligand uses its two or more donor atom simultaneously to bind a single metal ion. The number of such ligating groups, called Denticity of ligand.
-Ambidentate ligand is a ligand which has two different donor atoms and either or the two ligetes in the complex.
Example: Such ligands are $N{O_2}^ -$ and $SC{N^ - }$

Note:
The word Ligand is a latin word-ligare, which means to bind, was first used by Alfred stock in relation to silicon chemistry and ‘Dent’ term (Which is used like as monodentate, bidentate…etc) where the concept of teeth is introduced, this is the idea of bite angle etc.