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Cesium bromide crystallizes in cubic arrangement like CsCl. Given the ionic radii of Cs^(+) and Br^(–) are 1.88 Å and 1.82 Å respectively, determine the packing fraction. |
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Answer» SOLUTION : Here Cs+ ion is at body centre and Br– at the corners, therefore the relationship is `2(r_(+)+r_(-))=sqrt(3a)`=2(1.88+1.82) Å, Packing fraction `(phi)=(4)/(3)PI((r_(+)^(3)+r_(-)^(3))/(a^(3)))` `=(4)/(3)pi((1.88^(3)+(1.82)^(3))/(4.27)^(3))=0.6807` |
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