If $z$ represents the number of atoms in a unit cell of a close-packed structure with an $ABCABC$ stacking sequence,then the number of tetrahedral voids in the unit cell is ....

$A$ metal crystallises in an $FCC$ lattice with $ABCABC...$ packing. If the distance between the nearest neighbours is '$a$',then the distance between the centres of the nearest triangular voids of two consecutive layers is:

An alloy of metals $A$,$B$,and $C$ is found to have $A$ constituting a $ccp$ lattice. If $B$ atoms occupy the edge centers and $C$ is present at the body center,the formula of the alloy is:

In a crystal,atoms of $A$ form an $FCC$ lattice,atoms of $B$ occupy all octahedral voids,and atoms of $C$ occupy $25\%$ of the tetrahedral voids. The possible molecular formula of the compound is:

The limiting radius ratio for a tetrahedral void is:

In a solid compound,the atoms of $A$ form a face-centered cubic $(fcc)$ lattice,while atoms of $B$ occupy all octahedral voids and half of the tetrahedral voids. The molecular formula of the solid will be ........