Sodium chloride has rock salt structure, how many molecules are there in the unit cell of NaCl

Question

Sodium chloride has rock salt structure, how many molecules are there in the unit cell of NaCl (A) 2 (B) 4 (C) 6 (D) 8

Tardigrade Admin · Accepted Answer

In NaCl (rock salt): Number of Na +ions =12 (at edge centers) (1/4)+1 (at body centre) × 1=4. Number of Cl -ions =8 (at corners) × (1/8)+6 (at face centre) × (1/2)=4. Thus 4 formula units per unit cell.

Q. Sodium chloride has rock salt structure, how many molecules are there in the unit cell of $N a Cl$

$2$

$4$

$6$

$8$

In $N a Cl$ (rock salt): Number of $N a^{+}$ ions $= 12$ (at edge centers) $\frac{1}{4} + 1$ (at body centre) $\times 1 = 4$ .
Number of $C l^{-}$ ions $= 8$ (at corners) $\times \frac{1}{8} + 6$ (at face centre) $\times \frac{1}{2} = 4$ .
Thus 4 formula units per unit cell.

Q. Sodium chloride has rock salt structure, how many molecules are there in the unit cell of NaCl

2

4

6

8

In NaCl (rock salt): Number of Na+ions =12 (at edge centers) 41​+1 (at body centre) ×1=4. Number of Cl−ions =8 (at corners) ×81​+6 (at face centre) ×21​=4. Thus 4 formula units per unit cell.

Q. Sodium chloride has rock salt structure, how many molecules are there in the unit cell of $N a Cl$

$2$

$4$

$6$

$8$

In $N a Cl$ (rock salt): Number of $N a^{+}$ ions $= 12$ (at edge centers) $\frac{1}{4} + 1$ (at body centre) $\times 1 = 4$ .
Number of $C l^{-}$ ions $= 8$ (at corners) $\times \frac{1}{8} + 6$ (at face centre) $\times \frac{1}{2} = 4$ .
Thus 4 formula units per unit cell.