For a crystal of diamond, state :
The coordination number of each carbon atom.

Explanation

To determine the coordination number of each carbon atom in a crystal of diamond, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Coordination Number**:
- The coordination number is defined as the number of nearest neighboring atoms that surround a central atom in a crystal structure.

2. **Identify the Structure of Diamond**:
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