An element with molar mass 27 g mol−1 forms a cubic unit cell with edge length 4.05 ✕ 10−8 cm. If its density is 2.7 g cm−3, what is the nature of the cubic unit cell?
Molar mass of the given element, M = 27 g mol−1 = 0.027 kg mol−1
Edge length, a = 4.05 × 10−8 cm = 4.05 × 10−10 m
Density, d = 2.7 g cm−3 = 2.7 × 103 kg m−3
Applying the relation,
Where, Z is the number of atoms in the unit cell and NA is the Avogadro number.
Since the number of atoms in the unit cell is four, the given cubic unit cell has a face-centred cubic (fcc) or cubic-closed packed (ccp) structure.
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