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Interatomic spacing of iron atoms

  1. Jun 30, 2011 #1
    3.2kg of iron is required to make a hollow spherical shell having inner radius (r=3cm).outer radius(r=5cm).

    i)estimate density of iron. (ans :6.585g/cm^3) -not sure if its correct though
    ii) using (i),est interatomic spacing of the iron atoms. the atomic mass of iron is 55.9u.

    need help in (ii).is there like a formula for it?
  2. jcsd
  3. Jun 30, 2011 #2


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    Just report the avg. distance between the atomic centers ... in other words, assume atoms are point particles ... you should be able to answer the question using the appropriate manipulation of the quantities you have (i.e. density, mass, volume and atomic mass of iron).
  4. Jul 1, 2011 #3
    Your calculation of density is false - and not plausible, by the way.

    You lack a data to be able to evaluate the interatomic distance : the crystallograpic cell and the motive in the cell.
    The most simple lattice for the calculation is the face-centered cubic, but it rarely occurs in steels at room temperature, only in nickel alloys and manganese alloys (The Hadfield steel for instance). In a cfc an iron atom has 12 close neighbours. There are 4 atoms in the cubic cell.

    All the other steels and pure iron are centered cubic at room temperature, with 8 + 6 neighbours. And they are ferromagnetic.
    You easily find the parameter of the cc cell in the litterature, and on the net. There are 2 atoms in the cubic cell.
    Last edited: Jul 1, 2011
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