Which of the following best describes the Body Centred Cubic Structure (BCC)?

The Body Centred Cubic (BCC) structure is defined primarily by its unique arrangement of atoms within a cubic lattice. In a BCC structure, there are atoms positioned at each of the eight corners of the cube, which represent the corners of the cube, as well as a single atom located at the center of the cube itself. This means that both the corner atoms and the center atom contribute to defining the packing arrangement of the structure.

The arrangement allows for the BCC structure to have a distinctive atomic packing that provides certain mechanical properties, such as strength and ductility. This is in contrast to other crystal structures, where atoms may be arranged differently, such as in face-centered cubic or hexagonal close-packed structures.

When looking at the choices, the description of atoms at the corners of the cube accurately reflects part of the BCC structure, as does the mention of an atom being centered within the cube. Hence, the combination of the corner atoms (option A) and the center atom (option C) together form a complete representation of the BCC structure. This makes the selection of both features as part of the correct answer justified.