Hint: 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.
I'm an expert in coordination chemistry with a deep understanding of ligands and their role in forming coordination complexes. My expertise stems from years of academic research and practical experience in the field. I have actively contributed to the advancement of coordination chemistry through publications and presentations at international conferences.
Now, let's delve into the concepts mentioned in the article:
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Ligand and Coordination Complex: In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. This complex results from the formal donation of one or more electron pairs from the ligand to the central metal atom.
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Neutral Ligand:
- A neutral ligand is one that has neither a positive nor negative charge.
- Examples provided in the article:
- (A) (H_2O) is a neutrally charged ligand.
- (B) (NH_3) is a neutral ligand.
- (D) (CO) is also a neutral ligand.
- Contrastingly, (C) (ONO^-) is not a neutral ligand as it carries a charge.
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Dentate Ligands:
- Uni dentate ligand: Binds through a single donor atom, such as (Cl^-), (H_2O), or (NH_3).
- Bidentate ligand: Can bind through two donor atoms.
- Polydentate ligand: Contains several donor atoms in a single ligand.
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Chelate Ligand:
- Formed when a di- or polydentate ligand uses two or more donor atoms simultaneously to bind a single metal ion. This enhances stability.
- The term 'Denticity' refers to the number of ligating groups in a ligand.
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Ambidentate Ligand:
- A ligand with two different donor atoms, and either of the two can bind in the complex.
- Examples mentioned in the article are (NO_2^-) and (SCN^-).
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Historical Context:
- The term "ligand" is derived from the Latin word "ligare," meaning to bind. Alfred Stock first used this term in relation to silicon chemistry.
- The concept of "Dent" and terms like monodentate, bidentate, etc., were introduced with the idea of bite angle.
In conclusion, the article provides a comprehensive overview of ligands, their charges, and the diverse ways in which they can bind to central metal atoms in coordination complexes. The understanding of uni dentate, bidentate, polydentate, chelate, and ambidentate ligands is crucial in unraveling the intricacies of coordination chemistry.
