Chemical Forums
Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Q on July 05, 2021, 01:03:49 PM
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Experimentally it has been found that nickel has a density of 8,9 gcm-3 and that radius of its atom is 1,25 Å. Determine which type of cubic crystal lattice does nickel crystalize in.
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I don't know how to approach the problem because I cannot get a hang of how to calculate side of the unit cell. I know that it cannot possibly be cP (primitive) for the reason that the only metal that crystalizes in that crystal lattice is α-polonium. for that sake, it remains only cI or cF, but in both of these the relationship between radius and length of the side is differently expressed; cF: a=2√(2)r, cI: a=(4√(3)r)/(3)
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Have a look at, for instance, https://opentextbc.ca/chemistry/chapter/10-6-lattice-structures-in-crystalline-solids/
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How to calculate side of the unit cell ?
For cF (r - is the atom radius):
a = 2r √2
As of cI I think it will be:
a = 4r / √3
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How to calculate side of the unit cell ?
For cF (r - is the atom radius):
a = 2r √2
As of cI I think it will be:
a = 4r / √3
I understand that, but I have to figure out which of these two unit cells does nickel crystalize in.
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Figuring out may be a bad way.
Did you considered calculating density of cI and cF unit cells and comparing it to the experimental data ?