Which term refers to a symmetry element that relates to a displaced lattice during growth?

Which term refers to a symmetry element that relates to a displaced lattice during growth?

• A. Crystal Planes
• B. Doubly Refractive
• C. Glide Plane
• D. Doubling

Answer: (C)

Glide plane describes a symmetry operation that combines reflection across a plane with a translation along that plane by a fractional lattice vector. This means the pattern is mirrored and then shifted, so consecutive unit cells appear displaced relative to each other. That built-in displacement lines up with how the lattice can be carried along during growth, where the repeating motif appears in a shifted position as atoms add on. Hence this term is the one that specifically accounts for a displaced lattice through a symmetry operation. The other terms don’t describe this combined reflection-plus-translation idea: crystal planes refer to the orientation of planes in the lattice, not a symmetry operation; doubly refractive is an optical property (birefringence) and not a symmetry element; doubling isn’t a standard symmetry operation describing a displaced lattice.

Glide plane describes a symmetry operation that combines reflection across a plane with a translation along that plane by a fractional lattice vector. This means the pattern is mirrored and then shifted, so consecutive unit cells appear displaced relative to each other. That built-in displacement lines up with how the lattice can be carried along during growth, where the repeating motif appears in a shifted position as atoms add on. Hence this term is the one that specifically accounts for a displaced lattice through a symmetry operation.

The other terms don’t describe this combined reflection-plus-translation idea: crystal planes refer to the orientation of planes in the lattice, not a symmetry operation; doubly refractive is an optical property (birefringence) and not a symmetry element; doubling isn’t a standard symmetry operation describing a displaced lattice.