March 19, 2024, 05:27:23 AM
Forum Rules: Read This Before Posting


Topic: Crystals  (Read 1317 times)

0 Members and 1 Guest are viewing this topic.

Offline Q

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +0/-0
  • Gender: Male
Crystals
« on: July 05, 2021, 01:03:49 PM »
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.
________________________________
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)


Offline sjb

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 3653
  • Mole Snacks: +222/-42
  • Gender: Male
Re: Crystals
« Reply #1 on: July 05, 2021, 03:26:22 PM »

Offline Orcio_87

  • Full Member
  • ****
  • Posts: 440
  • Mole Snacks: +39/-3
Re: Crystals
« Reply #2 on: July 05, 2021, 04:01:46 PM »
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

Offline Q

  • New Member
  • **
  • Posts: 6
  • Mole Snacks: +0/-0
  • Gender: Male
Re: Crystals
« Reply #3 on: July 06, 2021, 04:54:06 AM »
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.

Offline Orcio_87

  • Full Member
  • ****
  • Posts: 440
  • Mole Snacks: +39/-3
Re: Crystals
« Reply #4 on: July 06, 2021, 05:07:14 AM »
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 ?

Sponsored Links