Question

Triclinic crystal system has the following unit cell dimensions:

• A. $a = b = c$ and $\alpha = \beta = \gamma = 90^\circ$
• B. $a = b \ne c$ and $\alpha = \beta = \gamma = 90^\circ$
• C. $a \ne b \ne c$ and $\alpha \ne \beta \ne \gamma \ne 90^\circ$
• D. $a = b \ne c$ and $\alpha = \beta = 90^\circ$, $\gamma = 120^\circ$

Hint:

Triclinic system = all lengths and all angles are unequal and not 90°.

Answer 1

The Correct Option is C

• The triclinic crystal system is the most general and least symmetric system.
• It has all sides of different lengths ($a \ne b \ne c$) and none of the angles are 90° ($\alpha \ne \beta \ne \gamma \ne 90^\circ$).
• This makes it distinct from other systems like cubic or tetragonal which have more symmetry.