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Homework Help: Calculate the Madelung Constant

  1. Oct 1, 2012 #1
    1. The problem statement, all variables and given/known data
    Calculate the Madelung constant for an octahedral arrangement of doubly charged anions about a doubly charged cation. Use r0 for the anion−cation distance. (Hint: Remember that the Madelung constant considers the sum of Coulomb interactions over all atom/ion pairs).


    2. Relevant equations

    Possibly helpful Equations
    EA=-(Mke2)/r0

    α=2M/((n1+n2)|Z1Z2|)

    EA=-(ke2α(n1+n2(|Z1Z2)/2r0

    3. The attempt at a solution

    So we have a theoretical bond pair X+2Y-2 with a coordination number of 6.

    I believe the next step should be to calculate EA, but I fail to see how to do that with out α.
     
  2. jcsd
  3. Oct 2, 2012 #2
    Your Madelung equation doesn't seem familiar to me, what textbook are you using?
     
  4. Oct 2, 2012 #3
    Last edited by a moderator: May 6, 2017
  5. Oct 2, 2012 #4

    Borek

    User Avatar

    Staff: Mentor

    None of these. Madelung constant is calculated just by summing electrostatic interactions between ions.
     
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