The coordination number of an atom in a body-centered cubic $(BCC)$ structure is:
[Assume that the lattice is made up of atoms.]

In a face-centered cubic lattice of $X$ and $Y$ atoms,$X$ atoms are present at the corners while $Y$ atoms are at the face centers. If two atoms of $X$ are missing from the corners,what is the formula of the compound?

What is the percentage of void space in $bcc$ type of unit cell (in $\%$)?

What is the coordination number in a hexagonal close-packed $(h.c.p.)$ structure?

The number of octahedral voids in a unit cell of a cubical closest packed structure is

If the length of the body diagonal of a $FCC$ unit cell is $x \ \mathring{A}$, the distance between two nearest octahedral voids in the cell in $\mathring{A}$ is