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The size of CI^(-) ion is 1.8 Å. The siz...

The size of `CI^(-)` ion is `1.8 Å`. The size of a cation for which a change in coordination just becomes possible from 6 to 8 in an ideal ionic crystal would be:

A

`0.7452Å`

B

`1.3176Å`

C

`0.405Å`

D

`1.8Å`

Text Solution

Verified by Experts

The correct Answer is:
2
`{:(R R R,,CN),(0.414 le (r_(+))/(r_(-)) lt 0.732,,6),(0.732 le (r_(+))/(r_(-)) lt 1.00,,8):}`
Hence use the RR of `0.732` corresponding to the said changeover from CN of 6 to CN of 8.
Hence cation size is `0.732xx1.8=1.3176Å`
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