In a compound,atoms of element $Y$ form a $ccp$ lattice and atoms of element $X$ occupy $2/3$ of the tetrahedral voids. What is the formula of the compound?

If the distance between the corner and the center of a cube is $x$,then the tetrahedral void will be at a distance of .... from the corner of the cube.

What type of crystal structure from the following has $52.36 \%$ packing efficiency?

$A$ compound formed by $Mg$,$Al$,and $O$ is found to have a cubic close-packed $(CCP)$ array of oxide ions,in which $Mg^{2+}$ ions occupy $\frac{1}{8}^{th}$ of the tetrahedral voids and $Al^{3+}$ ions occupy $\frac{1}{2}$ of the octahedral voids. The formula for the compound is:

In a compound,atoms of element $Y$ form $ccp$ lattice and those of element $X$ occupy $2/3$ of tetrahedral voids. The formula of the compound will be

$A$ metal having atomic mass $60.23 \ g/mol$ crystallises in $ABCABC$ close packing. Calculate the density of a single metal atom if the edge length of the unit cell is $10 \ \mathring{A}$. [Given: $N_A = 6.023 \times 10^{23}$]