What is the number of atoms per unit cell in a body-centered cubic $(BCC)$ unit cell?

An $AB_2$ type structure is found in

$A$ certain metal crystallizes in a $bcc$ lattice. The distance between the nearest neighbours is $433 \text{ pm}$. The distance between the next nearest neighbours is :- .............. $\text{pm}$

In a body-centered cubic $(BCC)$ unit cell,how many metal atoms surround the metal atom located at the center of the cell?

$A$ metal $X$ crystallises in a face-centred cubic arrangement with the edge length $862 \, pm$. What is the shortest separation of any two nuclei of the atom? ........... $\, pm$

The crystal structure of the solid compound $XY$ is similar to $NaCl$. If the radius of the cation $X^+$ is $100 \, pm$, then the radius of the anion $Y^-$ will be ......... $pm$.