If the radius of an anion is double that of a cation,the coordination number of the cation and the type of hole occupied are respectively:

$A$ solid $AB$ has a $NaCl$ structure. $B$ atoms are at the corners and all face-centered positions of the unit cell,while $A$ atoms occupy all the $O.H.V.$ (Octahedral Voids). If all the atoms from the face-centered positions along one axis are removed,what will be the resulting stoichiometry of the solid?

What is the coordination number of each sphere in a two-dimensional hexagonal close-packed structure?

The structure of $MgO$ is similar to $NaCl$. What would be the coordination number of magnesium?

The packing efficiency and coordination number of face-centred cubic $(FCC)$ lattice is

In $F.C.C.$,each face of the unit cell is shared equally by how many unit cells?