Distinguish between
a. Hexagonal and monoclinic unit cells
(b) Face-entred and end-centred unit cells

Explanation

To distinguish between the hexagonal and monoclinic unit cells, as well as between face-centered and end-centered unit cells, we can break down the characteristics of each type systematically.

### (a) Distinction between Hexagonal and Monoclinic Unit Cells:

1. **Edge Lengths**:
- **Hexagonal Unit Cell**: In a hexagonal unit cell, the edge lengths are such that \( a = b \neq c \). This means that the lengths of the edges along the base are equal, but the height is different.
- **Monoclinic Unit Cell**: In a monoclinic unit cell, the edge lengths are \( a \neq b \neq c \). All three edge lengths are different from each other.

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