Question

which of the following reflections would be missing in a bcc lattice: (100), (110), (111), (200), (210), (220), (211)? Answer the same question for an fcc lattice.

Answer 1

The (111), (210), and (211) reflections are missing in a BCC lattice, while all of the mentioned reflections are present in an FCC lattice.

Step-by-step explanation:

The BCC lattice is missing the reflections (111), (210), and (211). In a BCC lattice, the Miller indices of the reflections represent the planes that can be observed. The BCC lattice has certain limitations that exclude these specific planes from being observed.

On the other hand, all of the mentioned reflections are present in an FCC lattice. The FCC lattice is a close-packed structure, which means it has a higher packing efficiency compared to the BCC lattice. As a result, all the mentioned reflections are visible in an FCC lattice.

Answer 2

In a Body-Centered Cubic (BCC) lattice, the reflections that would be missing are:

(111)

(200)

(210)

For a Face-Centered Cubic (FCC) lattice, all the listed reflections: (100), (110), (111), (200), (210), (220), and (211) would be present.

FCC lattices allow for all these reflections due to their symmetric arrangement of atoms.

However, in a BCC lattice, certain reflections, particularly those related to higher Miller indices such as (111), (200), and (210), are not observed due to the specific arrangement and symmetry of atoms within the lattice structure.