Question

Which of the following statements about the packing of monatomic solids with different unit cells is incorrect?

O The coordination number of atoms in hcp and fcc structures is 12.
O A bcc structure has a higher packing efficiency than a simple cubic structure.
O The coordination number of atoms in simple cubic structures is 6.
O A bcc structure has a higher packing efficiency than a fcc structure. The coordination number of atoms in bcc structures is 8.

Answer 1

The incorrect statement is that a BCC structure has a higher packing efficiency than an FCC structure, when in fact, the FCC structure has the highest packing efficiency, occupying 74% of the volume.

Step-by-step explanation:

The statement that is incorrect among those given about the packing of monatomic solids with different unit cells is "A body-centered cubic (BCC) structure has a higher packing efficiency than a face-centered cubic (FCC) structure." The coordination number in BCC structures is 8, meaning each atom is surrounded by 8 nearest neighbors, while the coordination number of atoms in both HCP and FCC structures is 12, with atoms packed as closely together as possible in these lattice types. Also, BCC does have a higher packing efficiency than a simple cubic structure, but it is the FCC structure that has the highest packing efficiency, occupying 74% of the volume.