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Homework Help: Lattice constant, space between planes?

  1. Sep 23, 2015 #1
    1. The problem statement, all variables and given/known data

    the volume density of a body centered cubic lattice is 5.3*10^22

    Calculate the lattice constant, effective radius of atom, surface density on 110 plane, and distance between two nearest parallel 110 planes.
    2. Relevant equations
    4/a^3= volume density
    3. The attempt at a solution
    5.3*10^22=4/a^3, a=4.25 A

    2) effective atom radius, I know its( r1+r2) but I do not know what factor its multiplied by(i.e. 4*(r1+r2)/sqrt3, 2...) and I think I could solve for r^2 instead of r1 and r2.

    3) 2/(sqrt2*(4.25*10^-8)^2) = surface density?

    4) I do not know how to find distance between planes, is this r*2 ?
  2. jcsd
  3. Sep 28, 2015 #2
    For 2, you need to know the positions of two nearest neighbors. If you take an atom in the corner, where is its nearest neighbor?
    For 3, what is a 110 plane for a cubic lattice? Can you draw it?
    You can calculate the distance between planes either from geometry or by using the magnitude of the reciprocal lattice vector with the same indices.
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