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Homework Help: Distance to 3rd and 5th nearest ion to S2- in ZnS structure

  1. Oct 13, 2018 #1
    • Please post this type of questions in the HW section using the template and showing your work.
    Hey folks

    ZnS has a ccp structure with S2- ions forming FCC lattice with Zn2+ ions at half the tetrahedral voids


    Attached is a table showing no. of nearest neighbours and their distance for an S2- ion

    'a' is edge length of the unit cell

    I want to know how the distance to the 3rd & 5th nearest ion is √11a/4 & √19a/11, i.e how to prove this.


    Thanks ... any help is appreciated
  2. jcsd
  3. Oct 14, 2018 #2


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    Staff: Mentor

    Have you you tried to follow the geometry? Often it is enough to find right right triangles and use Pythagorean theorem.
  4. Oct 15, 2018 #3


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    Science Advisor

    I think those numbers are wrong. They're not what I get (with quick mental arithmetic).
  5. Oct 30, 2018 #4
    yes i did pythogarus & got it ... thanks ...
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