McCaw Chemistry

Resources written by Chas McCaw for sixth form chemistry teaching and beyond.

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Sodium 6: are all the sodium atoms equivalent?

Eight unit cells of sodium are shown to the left. The body-centre sodiums are shown in blue to distinguish them from the remaining sodiums occupying the unit cell corners. Are these two types of sodium atom equivalent in the structure? If they are equivalent we ought to be able to re-draw the unit cells with the corners at the positions presently occupied by the body-centre sodiums.

To consider how the unit cells may be drawn differently go to page 7.

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