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InterviewSolution
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An ionic compound is made up of cations A and anions `B`. if cations `A` are at the alternate corners and anions are at the alternate faces of the cubic unit cell then empirical formula of the compound will beA. `AB_(2)`B. `A_(2)B_(3)`C. `AB_(3)`D. `AB` |
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Answer» Correct Answer - 1 There are `8` corners. As there are four `A` cations at the alternate corners and contribution of each `=1//8` the number of `A` cation per unit cell is `= 4xx(1)/(8)=(1)/(2)` There are `6` square faces of the cubic unit cell. but there can be only two `B` anions on alternate faces (top, bottom, and left ,right or front, rear).As contributon of each of them `=(1)/(2)` The number of `B` anions per unit cell. `=2xx(1)/(2)=1` Hence simplest ratio of cations to anions. `(A:B)` `=(1)/(2):1` or `1:2`. thus the empirical formula of the ionic compound is `AB_(2)`. There are `4` body diagonals. Since atoms within the body of the unit cell are not shared by any other unit cell there are `8` more atoms giving a total of `9`atoms. |
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