If the radius of `Na^(+)` ion is `95 p m` and that of `Cl^(-)` ion is `181 p m`, then the coordination number if of Na+

Explanation

radius of `Na^(+)(r^(+))=9.5"pm"andCl^(-)(r^(-))=181"pm"`
`therefore"radius ratio"(r^(+)/(r^(-)))=(95"pm")/(181"pm")=0.524`
This radius ration lies between 0.414 - 0.732
Hence `Na^(+)` prefer to occupy octahedral site having co-ordination number = 6.