What is the difference between hcp and ccp structure ?

Asked by NAKSHATRA | 4th Aug, 2014, 06:24: PM

Expert Answer:

  1. Placing the third layer over the second layer: There are two possibilities:
    1. Covering the tetrahedral voids: Here, tetrahedral voids of the second layer may be covered by the spheres of the third layer. It gives rise to ABABAB… type pattern. The three-dimensional structure is called hexagonal close-packed structure.  Examples: Mg, Zn
    2. Covering the octahedral voids: Here, octahedral voids of the second layer may be covered by the spheres of the third layer. It gives rise to ABCABCABC… type pattern. The three-dimensional structure is called cubic close-packed structure or face-centred cubic structure.  Examples: Cu, Ag

Answered by Prachi Sawant | 5th Aug, 2014, 11:13: AM