In seven possible crystal system how many crystal system have more than one Bravais lattice ?

Answer

To solve the question of how many crystal systems have more than one Bravais lattice among the seven possible crystal systems, we can follow these steps:

### Step 1: Understand the Concept of Bravais Lattices
Bravais lattices are distinct arrangements of points in space that describe the periodic structure of a crystal. There are 14 unique Bravais lattices derived from the seven crystal systems.

### Step 2: Identify the Seven Crystal Systems
The seven crystal systems are:
1. Cubic
2. Tetragonal
3. Orthorhombic
4. Hexagonal
5. Triclinic
6. Monoclinic
7. Rhombohedral

### Step 3: Determine the Number of Bravais Lattices for Each Crystal System
Now, we will identify how many Bravais lattices each crystal system has:
- **Cubic**: 3 types (Simple Cubic, Body-Centered Cubic, Face-Centered Cubic)
- **Tetragonal**: 2 types (Simple Tetragonal, Body-Centered Tetragonal)
- **Orthorhombic**: 4 types (Simple Orthorhombic, Body-Centered Orthorhombic, Face-Centered Orthorhombic, End-Centered Orthorhombic)
- **Hexagonal**: 1 type (Simple Hexagonal)
- **Triclinic**: 1 type (Simple Triclinic)
- **Monoclinic**: 2 types (Simple Monoclinic, Base-Centered Monoclinic)
- **Rhombohedral**: 1 type (Simple Rhombohedral)

### Step 4: Count the Crystal Systems with More Than One Bravais Lattice
Now we will count the crystal systems that have more than one Bravais lattice:
- **Cubic**: More than one (3 types)
- **Tetragonal**: More than one (2 types)
- **Orthorhombic**: More than one (4 types)
- **Hexagonal**: Not more than one (1 type)
- **Triclinic**: Not more than one (1 type)
- **Monoclinic**: More than one (2 types)
- **Rhombohedral**: Not more than one (1 type)

### Step 5: Final Count
From the above analysis, the crystal systems with more than one Bravais lattice are:
1. Cubic
2. Tetragonal
3. Orthorhombic
4. Monoclinic

Thus, there are **4 crystal systems** that have more than one Bravais lattice.

### Final Answer
The answer is **4** crystal systems have more than one Bravais lattice.

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