The coordination number of a central ion may be obtained from

Options

A. a.The number of only anionic bonds formed with the surrounding ions
B. b.The number of coordinate bonds formed with the surrounding atoms
C. c.The number of ions of opposite charge immediately surrounding the specific ion .
D. d.None of the above

Answer

To determine the coordination number of a central ion in a coordination compound, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Coordination Number**:
- The coordination number is defined as the number of atoms, ions, or molecules that are directly bonded to the central metal ion in a coordination complex.

2. **Analyze Each Option**:
- **Option A**: "The number of only anionic bonds formed with the surrounding ions."
- This is incorrect because the coordination number includes all types of ligands, not just anionic ones. For example, water (H2O) is a neutral ligand and contributes to the coordination number.

- **Option B**: "The number of coordinate bonds formed with the surrounding atoms."
- This option is misleading. While it mentions coordinate bonds, it does not specify that these can include neutral ligands and does not accurately reflect the definition of coordination number, which is based on the number of ligands, not just the bonds.

- **Option C**: "The number of ions of opposite charge immediately surrounding the specific ion."
- This option is also incorrect. The coordination number can include neutral ligands and does not require the surrounding ions to be of opposite charge. For example, in the case of ferrous ion (Fe²⁺) complexed with neutral ligands like nitric oxide (NO), the surrounding ions can have the same charge.

- **Option D**: "None of them."
- This is the correct answer. None of the previous options accurately define how to determine the coordination number.

3. **Conclusion**:
- The coordination number of a central ion is determined by counting all the ligands (which can be anionic, cationic, or neutral) that are directly bonded to it, regardless of the charge.

### Final Answer:
The coordination number of a central ion may be obtained from **none of the options provided**.

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