The crystal structure of $NaCl$ is:

If three elements $X$,$Y$ and $Z$ crystallise in a $ccp$ lattice with $X$ atoms at the corners,$Y$ atoms at the cube centre and $Z$ atoms at the edges centre,the formula of the compound will be

The radius of the largest sphere which fits properly at the centre of the edge of a body-centered cubic $(BCC)$ unit cell is (Edge length is represented by $a$) (in $a$)

An ionic compound has unit cells consisting of $A$ ions at the corners of a cube and $B$ ions on the centres of the faces of the cube. The empirical formula of this compound is

An alloy of copper,silver,and gold is found to have copper atoms in an $fcc$ lattice. If silver atoms occupy the edge centers and gold atoms are present at the body center,what is the formula of the alloy?

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