NEET2003ChemistrySolid StateActual

What is the co-ordination number of sodium in Na ₂ O ?

Options

Correct answer

B. 4

Step-by-step solution

Na ₂ O has antifluorite structure. O ²⁻ ions constitute a ccp lattice and Na ⁺ ions occupy the tetrahedral voids, each O ²⁻ ion is in contact with 8 Na ⁺ ions and each Na ⁺ ion is in contact with 4 O ²⁻ ions. Thus C.N. of sodium in Na ₂ O =4 .

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