why tetragonal unit cells does not form fcc,bcc,end centred.

Asked by lokesh WARAN | 12th Feb, 2014, 07:04: AM

Expert Answer:

Dear lokesh

Thanks for asking us a question in Ask the Expert section of TopperLearning.com.

We have not understood the query that you have posted. We would request you to clarify / provide additional details so that we may answer this to the best of the ability.
However the following answer might clear your doubt.

In crystallography, the tetragonal crystal system is one of the 7 lattice point groups. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square base (a by a) and height (c, which is different from a).

There are two tetragonal crystal structure types. Bravais lattices: the simple tetragonal (from stretching the simple-cubic lattice) and the centered tetragonal (from stretching either the face-centered or the body-centered cubic lattice). One might suppose stretching face-centered cubic would result in face-centered tetragonal, but face-centered tetragonal is equivalent to body-centered tetragonal, BCT (with a smaller lattice spacing). BCT is considered more fundamental, so that is the standard terminology.


Topperlearning Team.

Answered by  | 14th Feb, 2014, 10:59: AM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.