For a crystal of sodium chloride, state:(i) The type of lattice in whi

1.	For a crystal of sodium chloride, state:(i) The type of lattice in which it crystallises.(ii) The coordination number of each sodium ion and chloride ion in the crystal lattice.(iii) The number of sodium ions and chloride ions present in a unit cell of sodium chloride.(iv) The structural arrangement of the sodium chloride crystal.
Answer» (i) Cubic close-packing (ccp) or face-centred cubic (fee) arrangement. (ii) The coordination of each Na⁺ ion as well as of each Cl^– ion is 6 and the structure possesses 6 : 6 coordination. (iii) The unit cell of sodium chloride, eight Cl^– ions are present at the comers and six Cl^– ions at the face-centres. Number of Cl^– ions = \(8\times\frac{1}{8}+6\times\frac{1}{2}\) = 4 Number of Na⁺ ions = \(12\times\frac{1}{4}+1\times1\) = 4 (iv) Rock salt structure.

For a crystal of sodium chloride, state:(i) The type of lattice in which it crystallises.(ii) The coordination number of each sodium ion and chloride ion in the crystal lattice.(iii) The number of sodium ions and chloride ions present in a unit cell of sodium chloride.(iv) The structural arrangement of the sodium chloride crystal.

Answer»

(i) Cubic close-packing (ccp) or face-centred cubic (fee) arrangement.

(ii) The coordination of each Na⁺ ion as well as of each Cl^– ion is 6 and the structure possesses 6 : 6 coordination.

(iii) The unit cell of sodium chloride, eight Cl^– ions are present at the comers and six Cl^– ions at the face-centres.

Number of Cl^– ions = \(8\times\frac{1}{8}+6\times\frac{1}{2}\) = 4

Number of Na⁺ ions = \(12\times\frac{1}{4}+1\times1\) = 4

(iv) Rock salt structure.