Question

Which among the following space groups is/are non-compatible with glide plane?

• A. Pab2₁
• B. Pnma
• C. P6₃/c
• D. P3c₁

Hint:

Space groups that belong to the orthorhombic and hexagonal crystal systems are often non-compatible with glide planes due to the symmetry of the crystal structure.

Answer 1

The Correct Option is A, C

Glide planes are symmetry elements in crystallography that combine reflection with translation. Not all space groups can have glide planes. Let's analyze the given space groups:
- (A) Pab2₁: This space group does not have a glide plane. It is part of the orthorhombic crystal system, where glide planes are not compatible with the symmetry. Therefore, (A) is non-compatible with a glide plane.
- (B) Pnma: This is a space group that contains a glide plane. It is part of the orthorhombic system, and glide planes are compatible with this symmetry. Thus, (B) is compatible with a glide plane.
- (C) P6₃/c: This space group is non-compatible with a glide plane. It belongs to the hexagonal crystal system, where glide planes are not allowed due to the symmetry of the system. Therefore, (C) is non-compatible with a glide plane.
- (D) P3c₁: This space group is compatible with a glide plane as it belongs to the trigonal system and does not violate the symmetry rules for glide planes. Therefore, (D) is compatible with a glide plane.
Thus, the correct answers are (A) and (C).