# Planar concentration

1. Sep 8, 2008

### elcotufa

1. The problem statement, all variables and given/known data
Niobium Nb has the BCC crystal with a lattice parameter of a= .3294 nm

Find the planar concentrations of atoms per m^2 of the (100, (110) and (111) planes.

The 100 plane has 1 atom on the plane (1/4 times 4)

the 110 plane has 2 atoms on the plane and using pythagorean theorem the long side is a*sqrt(2)

best pic I could find for the 111 plane
Now for the last plane (111) this is what I did

the area would be 1/2 base * height
the base is $$a*\sqrt2$$ and

pythagorean theorem to find the height is a^2 and half of the long side from plane (110) squared $$\sqrt{a^2+\frac{2a^2}4}=.4034nm$$

$$\frac12(.4034)10^{-9}(.3294)10^{-9}$$
Now how many atoms are on the plane? and are there mistakes in what I have done so far?

And how many atoms would that (111) plane have in a FCC model?
Answer would have number of atoms over area
Thanks for the help