Question

What is unit cell ?​

Answer 1

$Unit cell$

the smallest group of atoms which has the overall symmetry of a crystal, and from which the entire lattice can be built up by repetition in three dimensions.

Answer 2

$\huge{\underline{\underline{\mathfrak{Answer}}}}$

➡️The smallest group of atoms which has the overall symmetry of a crystal, and from which the entire lattice can be built up by repetition in three dimensions.

Ex - Calculate the number of unit cells in 8.1 gram of aluminium if it crystallizes in a fcc structure:-

n = given mass/molar mass.

=

Number of atoms = 8.1/27 × 6.022 ×× 10²³

Number of atoms in one unit cell = 4 (fcc)

Number of unit cell = [8.1/27 × 6.022 × 10²³]