Suggest the probable structures of the unit cells of the following each compound with the help of given data
`|{:(,,"Cationic radius","Anionic radius",),((a),RbBe,1.04Å,1.95Å,),((b),MeTe,0.65Å,2.21Å,),((c),MgO,0.65Å,1.40Å,),((d),BaO,1.35Å,1.40Å,):}|`

Answer

To determine the probable structures of the unit cells for the given compounds based on the provided cationic and anionic radii, we will analyze each compound individually.

### Step-by-Step Solution:

1. **Compound A: RbBe (Cationic radius: 1.04Å, Anionic radius: 1.95Å)**
- The cationic radius (Rb^+) is 1.04Å and the anionic radius (Be^2-) is 1.95Å.
- The ratio of cationic radius to anionic radius is approximately 0.53 (1.04/1.95).
- This ratio suggests that the structure could resemble that of Cesium Chloride (CsCl), which has a cubic structure where the cation is larger than the anion.
- **Probable structure**: CsCl structure.

2. **Compound B: MeTe (Cationic radius: 0.65Å, Anionic radius: 2.21Å)**
- The cationic radius (Me^+) is 0.65Å and the anionic radius (Te^2-) is 2.21Å.
- The ratio of cationic radius to anionic radius is approximately 0.29 (0.65/2.21).
- This ratio indicates a structure similar to Zinc Sulfide (ZnS), which has a sphalerite or zinc blende structure.
- **Probable structure**: ZnS structure.

3. **Compound C: MgO (Cationic radius: 0.65Å, Anionic radius: 1.40Å)**
- The cationic radius (Mg^2+) is 0.65Å and the anionic radius (O^2-) is 1.40Å.
- The ratio of cationic radius to anionic radius is approximately 0.46 (0.65/1.40).
- This ratio is indicative of a structure similar to Sodium Chloride (NaCl), which has a face-centered cubic structure.
- **Probable structure**: NaCl structure.

4. **Compound D: BaO (Cationic radius: 1.35Å, Anionic radius: 1.40Å)**
- The cationic radius (Ba^2+) is 1.35Å and the anionic radius (O^2-) is 1.40Å.
- The ratio of cationic radius to anionic radius is approximately 0.96 (1.35/1.40).
- This ratio suggests a structure similar to Cesium Chloride (CsCl), as it is close to 1, indicating a cubic arrangement.
- **Probable structure**: CsCl structure.

### Summary of Probable Structures:
- **A: RbBe** - CsCl structure
- **B: MeTe** - ZnS structure
- **C: MgO** - NaCl structure
- **D: BaO** - CsCl structure