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Gernald
Jan 29, 2009, 11:14 AM
I have Cs (169pm) and Cl (167pm) how do I calculate the diagonal of the unit cell for CsCl?

I'm so lost the only thing I can think to do is have d=2(169)+2(167) so d would equal 672.
Is this right or am I having wishful thinking?

sarnian
Jan 29, 2009, 06:55 PM
Gernald

This seems a chemical question.
I'm lost here too : what do you mean precisely with unit cell? Please specify.
Also "169pm" : part per million?
Also "the diagonal of the unit cell for CsCl"?

Gernald
Jan 29, 2009, 07:10 PM
Yea it's a chemical question
Pm-picometer
Unit cell: A unit cell is the smallest unit of a crystal, which, if repeated, could generate the whole crystal.
The unit cell looks like a square and the diagonal passes through it.

Capuchin
Jan 30, 2009, 06:13 AM
I'm a little confused here, what exactly do the numbers refer to? Some kind of bond length?

The actual maths you need to do should be simple pythagoras.

sarnian
Jan 30, 2009, 03:34 PM
Gernald

Thanks for the data.
Sorry, but this is not my strongest subject, so I can only post thoughts...
Re. the problem of size of the unit cells : you mentioned square, but this is about a cell. So should we not refer to a cube?
Besides that : in the case of Cs and Cl we deal with atoms, but with CsCl with a molecule, whereby the structure is important for size.

Have a look at this website on the CsCl structure ! (http://cst-www.nrl.navy.mil/lattice/struk/b2.html)
I hope this gives you some idea how to solve the problem.

Gernald
Jan 31, 2009, 07:48 PM
I'm a little confused here, what exactly do the numbers refer to? some kind of bond length?
The actual maths you need to do should be simple pythagoras.

Oh sorry, the numbers are the radius of the molecules. And I think you're right pythagoras should do it. And Sarnain yes it is a cube, again I was writing fast and wrote the counterpart of the cube.

Thanks Capuchin for all the help (with everything), I'd rate you, but the site won't let me.