a. `MgO` has the structure of `NaCl` and `TICI` has the structure of `CsCl` . What are the coordiantion number of the ions in `MgO` and `TICI`?
If the closed-packed cations in an `XY`-type solid have a raidus of `73.2` pm, what would be the maximum and minimum sizes of the anions filling voids?
c. `Fe_(2)O_(3)` (haematite) forms ccp arrangement of `O^(2-)` ions with `Fe_(3+)` ions occupying initerstitial positions. Predict whether `fe^(3+)` ions are in the `OV` or `TV`. Given `r_(Fe^(3+)) = 0.7 Å` and `r_(O^(2-)) = 1.4 Å`
d. A solid `XY` has `CsCl`-type structure. The edge length of the unit cell is `400 pm` Calculate the distance of closest approach between `X^(o+)` and `Y^(ɵ)` ions.

Answer

C.N. of `Mg^(2+)&O^(2-)` ions =6, C.N. of `Cs^(+)&Cl^(-)` ions =8

Explanation

C.N. of `Na^(+)` in NaCl = 6 , C.N of `Cl^(-)` in NaCl = 6.
Hence in MgO C.N. of `Mg^(2+)` is also = 6 , that of `O^(2-)=6`
We know that in CsCl
C.N. pf `Cs^(+)=8` , C.N. of `Cl^(-)=8`
Hence, `Ti^(+)` and `Cl^(-)`,in TiCl have also C.N. 8 each.