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Gold has a close-packed structure which can he viewed as spheres occupying 0.74 of the total volume. If the density of gold is 19.3 g/cc, calculate the apparent radius of a gold ion in the solid. |
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Answer» Solution :Gold has a close-packed structure with a packing fraction value of 0.74. This SHOWS that it has a face-centred cubic cell. The number of IONS in a face-centred unit cell is 4. Now, density `=("mass of unit cell")/("VOLUME of unit cell")` or `19.3 = (4 xx (197) xx 1.66 xx 10^(-24))/a^(3) , a = 4.07 xx 10^(-8)` CM. In a face-centred cubic cell, radius `=(sqrt(2)a)/4 = (sqrt(2) xx 4.07 xx 10^(-8))/4 = 1.439 xx 10^(-8) cm` |
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