What is the coordination number of sodium in $Na_2O$?

Explain how much portion of an atom located at $(i)$ corner and $(ii)$ body centre of a cubic unit cell is part of its neighbouring unit cell.

What is the total number of particles present in a base-centred unit cell?

In a solid $AB$,$A$ atoms are in $ccp$ arrangement and $B$ atoms occupy all the octahedral sites. If two atoms from the opposite faces are removed,then the resultant stoichiometry of the compound is $A_{x} B_{y}$. The value of $x$ is ..... [nearest integer]

Structure similar to zinc blende is found in

Which type of cubic lattice has the maximum number of atoms per unit cell?