The ionic radii of Rb+ and I- respectively are 1.46 Å and 2.16Å. The very most probable type of structure exhibited by it is: (a) CsCl type (b) ZnS type (c) Nacl type (d) CaF2 type
Answer: (c) (rC+)/(ra-) = 1.46/2.16 = 0.676
It permits co-ordination number 6 and octahedral structure of type Nacl.