Question #04d90
1 Answer
Jan 29, 2017
It may not matter because the question talks about the faces of the cell, not the corners of the cell. Here is a list of all the common unit cells in an undergraduate class:
- Primitive cubic (also known as simple cubic)
- Face-centered cubic (FCC; also known as cubic close-packed, CCP)
- Body-centered cubic (BCC)
- Hexagonal close-packed (HCP)
)
)
Although the question doesn't specify which unit cell (though it should, to not confuse the student!), we can figure out that the only ones that have an atom on a face are the FCC and the HCP unit cells.
The FCC unit cell has six 1/2-atoms total on the faces, while the HCP, from what I can tell, has two 1/2-atoms total on the top and bottom faces.
No unit cell that you would need to know about has any different than 1/2 an atom on a face.
