The radius ratio of cation to anion for a triangular void is ....

An octahedral void is surrounded by how many spheres?

In a $ccp$ structure of $X$ atoms,$Y$ atoms occupy half of the octahedral voids. If one $X$ atom and one $Y$ atom in each unit cell are replaced by a $Z$ atom,the molecular formula of the solid will be:

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?

The vacant space in $bcc$ lattice unit cell is ............ $\%$

In a close-packed arrangement,$A$ type of atoms are at corners,$B$ type of atoms are at face centers,$C$ type of atoms are at tetrahedral voids,and $D$ type of atoms are at octahedral voids. If all the atoms along any one body diagonal are removed,what will be the formula of the compound?