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Homework Help: Primitive cell

  1. Jan 16, 2008 #1
    [SOLVED] primitive cell

    1. The problem statement, all variables and given/known data
    Could someone give me a mathematically rigorous of a primitive cell? I have read like 4 different definitions and none of them seem mathematically rigorous.
    I think Wikipedia's definition is particularly ambiguous: "a minimum cell corresponding to a single lattice point" ?
    In what sense is minimum being used? In what sense is cell being used?

    EDIT: this should probably be in the Advanced Physics section but I cannot delete it or move it

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 16, 2008 #2
    Someone PLEASE HELP this problem is driving me insane.

    In the picture in the Crystal Structure section of http://en.wikipedia.org/wiki/NaCl, what is the primitive cell AND WHY?
    Last edited: Jan 16, 2008
  4. Jan 16, 2008 #3
    I think I understand now. Go to http://www.neutron.anl.gov/hyper-physics/bravais.html [Broken].

    The primitive cell of the cubic face-centered structure of the NaCl lattice IS NOT THE CUBE. The cube is the CONVENTIONAL cell for the primitive face-centered cubic structure (e.g. NaCl) but IT CANNOT BE THE PRIMITIVE CELL BECAUSE IT CONTAINS 4 LATTICE POINTS WHICH IS MORE THAN 1.

    The primitive cell of the the fcc crystal is actually a rhombohedron.
    Last edited by a moderator: May 3, 2017
  5. Jan 17, 2008 #4


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    You got the idea :) Crystal structure is quite hard in the beginning, many new things to learn.
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