Question

ion ionic radius
ca⁺ 167 pm
f⁻ 133 pm
based on the data in the table, which of the following diagrams best depicts the structure of the ionic solid csf?
choose 1 answer

Explanation:

Step1: Analyze ion - size ratio

The ionic radius of \(Cs^+\) is 167 pm and of \(F^-\) is 133 pm. The ratio of cation to anion radius \(\frac{r_{cation}}{r_{anion}}=\frac{167}{133}\approx1.256\). In ionic solids, the coordination number and structure depend on this ratio. For a ratio in the range of 0.732 - 1.000, the coordination number of the cation is 8 and the structure is a cesium - chloride type structure.

Step2: Examine ion - size representation in diagrams

In a cesium - fluoride (CsF) ionic solid, since \(Cs^+\) is larger than \(F^-\), the larger circles should represent \(Cs^+\) and the smaller circles should represent \(F^-\).

Step3: Select the correct diagram

Looking at the diagrams, the correct one should have larger \(Cs^+\) ions and smaller \(F^-\) ions arranged in a pattern that reflects the cesium - chloride structure (cations surrounded by 8 anions and vice - versa). Diagram D shows larger ions (representing \(Cs^+\)) and smaller ions (representing \(F^-\)) in an appropriate ionic - solid arrangement.

Answer:

D.