what do you meant by radius ratio?what is its application?
Answers
Answer:
The ratio of the radius of the smaller ion to that of the larger; commonly cation to anion. Radius ratios are used to predict coordination numbers of anions about cations in ionic crystal structures.
Answer: Radius Ratio refers to as the ration of smaller ionic radius (cation) by the larger ionic radius (anion).
∴ Radius ratio = Radius of cation/ Radius of anion = r+/r-
Radius ration plays an important role in determining the structures of ionic solids and coordination number of ions.
For example:
⇒For cation to occupy tetrahedral voids
Radius ration has range = 0.225 - 0.414
Coordination number = 4
⇒For cations to occupy octahedral voids
Radius ratio has range = 0.414 - 0.732
Coordination number = 6
If radius ratio is more that 0.225 cation will occupy trigonal void [Coordination number = 3]
If radius ration is more than 0.732 cation will occupy cubic void [Coordination number = 8]
Explanation: