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The Solid State

Question
CBSEENCH12010304

Aluminum crystallizes in an fcc structure. Atomic radius of the metal is 125 pm. What is the length of the side of the unit cell of the metal? 

Solution

Aluminum crystallizes in FCC structure atomic radius (r) = 125 pm

Length of the side of the unit cell in FCC structure,   straight a equals fraction numerator 4 over denominator square root of 2 end fraction straight r space equals space 2 square root of 2 straight r end root

 Therefore            a= 2 x 1.414 x 125

a = 353.5 pm