Question

The structure of \[{\text{N}}{{\text{a}}_{\text{2}}}{\text{O}}\] crystal is:
(A) \[{\text{CsCl}}\]type
(B) \[{\text{NaCl}}\]type
(C) \[{\text{KCl}}\]type
(D) Anti-fluorite

Answer 1

Hint: Sodium oxide has a chemical formula \[{\text{N}}{{\text{a}}_{\text{2}}}{\text{O}}{\text{.}}\] The main use of this chemical is in ceramics and in the formation of glasses. It is a base anhydride of sodium hydroxide \[{\text{(NaOH)}}{\text{.}}\] This means that when water is added to sodium oxide, sodium hydroxide is formed. The reaction is as follows –
\[N{a_2}O{\text{ }} + {\text{ }}{H_2}O{\text{ }} \to {\text{ }}2NaOH\]

Complete step by step answer:
Sodium oxide or \[{\text{N}}{{\text{a}}_{\text{2}}}{\text{O}}\] possesses the structure of anti-fluorite. Sodium ions are smaller in size than the oxide ions so they go to the voids. Moreover, the number of sodium ions present is twice that of the oxide ions so all the tetrahedral voids get filled by sodium ions. The oxide ions are larger in size so they occupy the face and corners of the lattice. Therefore, the structure formed is all the oxide ions occupy the face and corners while the sodium ions occupy the tetrahedral voids.
   
The anti-fluorite structure is derived from fluorite structure by interchanging the positive and negative positions in the lattice crystal.

Hence, the correct answer is (D) i.e., anti-fluorite.

Note: Sodium oxide is widely used in the manufacturing of ceramic and glass products. Also, sodium oxide is insoluble in water, but when added to water, it would result in the formation of sodium hydroxide.