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In corundum, oxide ions are arranged in ...

In corundum, oxide ions are arranged in hcp arrangement and the aluminium ions occupy two-third of the octahedral holes. Its formula is `:`

A

`Al_(2)O_(4)`

B

`Al_(2)O_(3)`

C

`Al_(3)O_(4)`

D

`AlO_(2)`

Text Solution

Verified by Experts

The correct Answer is:
B
In a close packed arrangement, there is one octahedral site corresponding to each atom constituting the lattice.
No. of oxide ions per unit cell in hcp = 6.
No. of octahedral holes `= 6 xx1 = 6`
Formula of compound `=Al_(4) O_(6) ` or `Al_(2) O_(3)`
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