The smallest repeating pattern which when repeated in three dimensions results in the crystal of the substance is called

Options

A. space lattice
B. crystal lattice
C. unit cell
D. coordination number

Answer

To solve the question, "The smallest repeating pattern which when repeated in three dimensions results in the crystal of the substance is called," we can follow these steps:

### Step-by-Step Solution

1. **Understand the Concept**: The question is asking about a specific term used in crystallography. We need to identify what the smallest repeating unit in a crystal structure is.

2. **Identify the Options**: The options provided are:
- A) Space lattice
- B) Crystal lattice
- C) Unit cell
- D) Coordination number

3. **Analyze Each Option**:
- **Space lattice**: This term refers to the three-dimensional arrangement of points (lattice points) in space. It is not the smallest repeating unit.
- **Crystal lattice**: This is a broader term that refers to the entire arrangement of atoms or molecules in a crystal. It encompasses multiple unit cells, so it is also not the correct answer.
- **Unit cell**: This is defined as the smallest repeating unit in a crystal lattice. When a unit cell is repeated in three dimensions, it forms the entire crystal structure. This matches the description given in the question.
- **Coordination number**: This term refers to the number of nearest neighbors surrounding an atom in a crystal structure. It does not describe a repeating pattern.

4. **Select the Correct Answer**: Based on the analysis, the correct answer is **C) Unit cell**.

5. **Conclusion**: The unit cell is indeed the smallest repeating pattern that, when repeated in three dimensions, results in the formation of the crystal of the substance.

### Final Answer
The smallest repeating pattern which when repeated in three dimensions results in the crystal of the substance is called **Unit Cell**.

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