For an ionic crystal of the general formula AX and coordination number 6, the value of radius ratio will be

for co-ordination no 6 / 0.414 r r to 0.732 106. In the crystals, which of the following ionic compounds would you expect maximum distance between centres of cations and anions (a) LiF (b) CsF (c) CsI (d) LiI id state 16 Sol. The maximum distance between the centres of cations and anions is the ionic radius. The ionic radius increases down the group. Which means that the distance between the centres of the cations and anions also increases. Between Cs and Li, Cs is present down the group and has a larger size and between F and I, I is present down the group and has a larger size. Hence,