For an ionic crystal of the type $AB$,the value of the limiting radius ratio is $0.40$. This value suggests that the crystal structure should be:

In a hexagonal close packing $(hcp)$ lattice,each sphere touches ................... spheres in its own layer.

Coordination numbers of $Zn^{2+}$ and $S^{2-}$ in the crystal structure of wurtzite are

If three elements $A, B, C$ crystallize in a cubic solid lattice with $B$ atoms at the cubic centers, $C$ atoms at the center of edges, and $A$ atoms at the corners, then the formula of the compound is

How many nearest neighbours are there for $Si$ and $O$ atoms in quartz crystals?

If the number of atoms per unit cell in a crystal is $2$,the structure of the crystal is: