Which of the following lattices has the highest packing efficiency: $(i)$ simple cubic,$(ii)$ body-centred cubic,and $(iii)$ hexagonal close-packed lattice?

Calculate the total number of tetrahedral and octahedral voids formed in $0.6 \ mol$ of a compound if it forms $hcp$ structure.

Vacant space in body centered cubic $(BCC)$ lattice unit cell is about (in $\%$)

In a solid compound,the oxide ions are arranged in $CCP$. Cations $A$ occupy $1/6^{th}$ of the tetrahedral voids and cations $B$ occupy one third of the octahedral voids. The probable formula of the compound is

In a crystalline compound,$A$ atoms occupy all corners,$B$ atoms occupy all face-centered positions,$C$ atoms occupy all edge centers,and $D$ atoms occupy all tetrahedral voids formed by $A$ and $B$ atoms. Find the formula of the compound.

$A$ 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: $N_A = 6.023 \times 10^{23}$]