Write the name of the following ligands and classify their denticity
(a) o- phen (b) `NOS^(-)`

Answer

To solve the question, we will identify the names of the ligands and classify their denticity step by step.

### Step 1: Identify the first ligand (o-phen)
- The first ligand given is "o-phen" which stands for "o-phenanthroline".
- The systematic name of this ligand is 1,10-phenanthroline.

### Step 2: Determine the structure of 1,10-phenanthroline
- 1,10-phenanthroline consists of three fused aromatic rings with two nitrogen atoms in the structure.
- Each nitrogen atom has a lone pair of electrons that can be donated to a central metal atom.

### Step 3: Classify the denticity of 1,10-phenanthroline
- Since there are two nitrogen atoms, each donating one lone pair, 1,10-phenanthroline is classified as a bidentate ligand.
- Bidentate means it has two donor sites.

### Step 4: Identify the second ligand (NOS^(-))
- The second ligand is "NOS^(-)" which is known as thionitrito.
- The systematic name for this ligand is "N-thionitrito".

### Step 5: Determine the structure of N-thionitrito
- In N-thionitrito, the nitrogen atom has a lone pair of electrons that can be donated to a central metal atom.

### Step 6: Classify the denticity of N-thionitrito
- Since there is only one nitrogen atom donating one lone pair, N-thionitrito is classified as a monodentate ligand.
- Monodentate means it has one donor site.

### Final Answer
- (a) 1,10-phenanthroline - Bidentate ligand
- (b) N-thionitrito (NOS^(-)) - Monodentate ligand

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