Dear Mozahid,

The perovskite sample of Na0.5Bi0.5TiO3 crystallizes into two different crystal structures. (1) It may be tetragonal with space gruop P4bm (5.5179; 5.5179; 3.9073; 90; 90; 90 ) or (2) may be rhombohadral with space group R-3c ( 5.4887; 5.4887; 13.5048; 90; 90; 120). The formation of crystalline phase may depend on synthesis route as well as on starting materials used during synthesis. It will be only confirmed by observing XRD pattern of the sample. There several literatures available online you can take help from there. I hope it will help you.

I agree with Dinesh Kumar

Dear Mr. Dinesh Kumar ,

Please, you can send me a clear manuscript in order to calculate this values from XRD.... Because I'm chemist not physics so my information in this work is low and I need to be it strong.

Best regards,

These articles may help you...

Article The tetragonal phase of Na(0.5)Bi(0.5)TiO3--a new variant of...

Article Investigation of the Structure and Phase Transitions in the ...

Thank you very much Dinesh Kumar for your valuable comment...

R3c

You can refer these articles.

Article Ferroelectric-ferroelectric phase coexistence in Na1/2Bi1/2TiO3

Article Local structural disorder and its influence on the average g...