The crystal system without any element of symmetry is

Options

A. monoclinic
B. hexagonal
C. triclinic
D. cubic

Answer

To solve the question "The crystal system without any element of symmetry is," we will analyze the properties of different crystal systems and identify which one lacks symmetry elements.

### Step-by-Step Solution:

1. **Understand Crystal Systems**: There are seven different crystal systems in crystallography: cubic, tetragonal, orthorhombic, hexagonal, rhombohedral, monoclinic, and triclinic. Each has distinct symmetry properties.

2. **Identify Symmetry Elements**: Symmetry elements in crystals include:
- Rotational axes (C_n)
- Mirror planes
- Inversion centers

3. **Analyze Each Crystal System**:
- **Cubic**: Has multiple symmetry elements, including C4 and C3 axes.
- **Hexagonal**: Has a C6 rotational axis of symmetry.
- **Monoclinic**: Has a C2 rotational axis of symmetry.
- **Triclinic**: Lacks any symmetry elements. There are no rotational axes, mirror planes, or inversion centers.

4. **Conclusion**: Among the listed options, the triclinic crystal system is the only one that does not have any element of symmetry.

5. **Final Answer**: The crystal system without any element of symmetry is **triclinic**.