Which of the following statements is not correct?

Options

A. The fraction of the total volume occupied by the atoms in a primitive cell is 0.48.
B. Molecular solids are generally volatile
C. The number of carbon atoms in a unit cell of diamond is 8
D. The number of Bravais lattices in which a crystal can be categorized is 14

Answer

A

Explanation

Volume of atoms in a unit cell (v)= `4/3 pi r^3`
For primitive celle `r=a/2`
`v=4/3 pi(a/2)^3=(pi a^3)/(6)`
Volume of the unit cell (V)= `a^3`
Thus, total volume occupied by the atom
`=("Volume of the atoms in unit cell")/("Volume of unit cell")`
`=(pi a^3)/(6)xx(1)/(a^3)=pi/6=052`
Hence. Statement a. is incorrect.