=> R(+) / R(-) = .414
=> R(+) + R(-) = âˆš2(R-)
=> R(+) = R(-)*(.414)
=> R(+) = 250 * .414
=> R(+) = 104(approx.)
Therefore (A) is the answer
5 Answers
Manish Shankar
·2014-03-09 21:51:04
A^{+} is in the octahedral void of X^{-}.
2r^{+}+2r^{-}=2âˆš2r^{-}
r^{+}=(âˆš2-1)r^{-}=0.414*250=103.5â‰ˆ104 pm
Aditya Agarwal
·2014-03-10 00:02:51
sir, what is the fundamental mistake in considering r^{+} =0.732r^{-}?
what will happen if r^{+}r^{-}=0.732(just less than)
then what is the implication of saying if 0.414 â‰¤r/R â‰¤0.732, it is an octahedral void?
Manish Shankar
·2014-03-10 22:36:34
then there is a concept of tightly fit and loosely fit.
when r/R=0.414 it is tightly fit.
as we go on increasing the ratio, it becomes loose
and after 0.732 it is so loose that it changes to BCC
Aditya Agarwal
·2014-03-13 03:35:26
So sir if not mentioned, we always take it to be tightly fit?
- Rajiv Agarwal yes, take it as ideal packing (tightly fit = all are touching each other)Upvote·0· Reply ·2014-03-14 21:58:57
- Aditya Agarwal Ok, sir. Thank You. :)
Prashant Kulthia
·2014-03-15 10:14:49