The close packing that represents the $ABC ABC......$ order is:

If a compound (oxide) has an $hcp$ arrangement and the cations $M$ occupy two-thirds of the octahedral voids,the formula of the compound is:

Define: Packing Efficiency.

In an ionic solid, anions $(B)$ are arranged in an $hcp$ array and cations $(A)$ occupy $1/2$ of the tetrahedral voids. What is the formula of the ionic compound?

$A$ solid is made of two elements $X$ and $Z$. The atoms $Z$ are in $CCP$ arrangement while the atoms $X$ occupy all the tetrahedral sites. What is the formula of the compound?

$A$ solid contains elements $A$ and $B$. Anions of $B$ form $ccp$ lattice. Cations of $A$ occupy $50 \%$ of octahedral voids and $50 \%$ of tetrahedral voids. What is the molecular formula of the solid?