Dear Sushmita, this is a very interesting technical question. As a synthetic inorganic chemist I'm not a proven expert in this field. However, I came across a few potentially useful research articles which might help you in your analysis. For example, please have a look at the following interesting paper about nanoindentation:

Nanoindentation of Molecular Crystals: Lessons Learned from Aspirin

Article Nanoindentation of Molecular Crystals: Lessons Learnt from Aspirin

The paper has been posted as public full text on RG, so it is freely available as pdf file. Also please see:

Nanoindentation for probing the mechanical behavior of molecular crystals–a review of the technique and how to use it

Article Nanoindentation for probing the mechanical behavior of molec...

In general I would say that you cannot predict the crystal shape of a certain compound. Depending on the solvent and the crystallization conditions, crystals can be e.g. compact, flat, plate-like, prism-shaped or needle-like. In my personal experience the only way to perhaps alter the crystal shape is to change the solvent used for crystallization.

I hope this helps. Good luck with your research and best wishes, Frank Edelmann

Dear Frank,

Thank you for sharing the research articles and your valuable opinion. Perhaps, I need to find out which solvent to use that might produce a relatively flat surfaced crystal.

Dear Sushmita Majumder thank you for your response. Yes, indeed, try to find out a new solvent or solvent mixture if you want to change the crystal habit. It doesn't make sense to try the same solvent again and again. If a certain solvent yields e.g. needle-like crystals (which are certainly useless for your purpose), it will always produce needle-like crystals. Another option would be to change the crystallization technique as well, e.g. use a diffusion technique instead to cooling a saturated solution. For some useful guides to crystallization please have a look at the attached articles.