`AX,AY,BX`, and `BY` have rock salt type structure with following internuclear distances:
`|{:("Salt","Anion-anion","Cation-anion"),(,"distance in"Å,"distance in"Å),(AX,2.40,1.70),(AY,1.63,1.15),(BX,2.66,1.88),(By,2.09,1.48):}|`
A salt `MY` crystallizes in the `CsCl` structure. The anions at the corners touch each other and cation is in the centre. The radius ratio `(r_(o+)//r_(Θ))` for this structure is

Options

A. `0.225`
B. `0.414`
C. `0.732`
D. `1.0`

Explanation

To solve the problem, we need to find the radius ratio \( \frac{r_{+}}{r_{-}} \) for the cesium chloride (CsCl) structure, where \( r_{+} \) is the radius of the cation and \( r_{-} \) is the radius of the anion.

### Step-by-Step Solution:

1. **Understanding the Structure**:
- CsCl has a body-centered cubic (BCC) structure.
- The anions are located at the corners of the cube, and the cation is located at the center.

2. **Finding the Distance Between Anions**:
- The distance between two opposite corner anions (let's say A and B) can be calculated using the body diagonal of the cube.
- The body diagonal \( d \) of a cube with edge length \( a \) is given by:
\[ d = \sqrt{3}a \]

3. **Relation of Distances**:
- In the CsCl structure, the distance between the centers of the anions (corner anions) is equal to the distance from the center of the cation to the center of a corner anion plus the distance from the center of the cation to the center of the opposite corner anion.
- This can be expressed as:
\[ d = 2r_{-} + 2r_{+} \]
- Therefore, we can write:
\[ \sqrt{3}a = 2r_{-} + 2r_{+} \]

4. **Finding the Edge Length**:
- For the CsCl structure, the edge length \( a \) can be expressed in terms of the radii:
\[ a = 2r_{-} \]
- Substituting this into the equation for \( d \):
\[ \sqrt{3}(2r_{-}) = 2r_{-} + 2r_{+} \]

5. **Simplifying the Equation**:
- Dividing the entire equation by 2:
\[ \sqrt{3}r_{-} = r_{-} + r_{+} \]
- Rearranging gives:
\[ r_{+} = \sqrt{3}r_{-} - r_{-} = (\sqrt{3} - 1)r_{-} \]

6. **Finding the Radius Ratio**:
- The radius ratio \( \frac{r_{+}}{r_{-}} \) can now be calculated:
\[ \frac{r_{+}}{r_{-}} = \frac{(\sqrt{3} - 1)r_{-}}{r_{-}} = \sqrt{3} - 1 \]
- Evaluating \( \sqrt{3} \):
\[ \sqrt{3} \approx 1.732 \]
- Thus:
\[ \frac{r_{+}}{r_{-}} \approx 1.732 - 1 = 0.732 \]

### Conclusion:
The radius ratio \( \frac{r_{+}}{r_{-}} \) for the CsCl structure is approximately **0.732**.