Hello Amran Hossain,

Symmetry is intriguing, because crystallography and computational chemistry deals it differently. In crystallography, you can model a dopant atom in the same site as the non dopant, changing the occupation. This means that the symmetry of the cell is "preserved". But computational doesn't do it. You can't put 2 different atoms in the same place, and state "50% occupancy for each". You have to describe them explicitly. So if you have a CoSb2.8Ge0.2 compound, it means that in 30 original Sb sites, 28 are still Sb but now 2 are Ge. And you must draw this proportion explicitly, and try to find a way to model it in a way a symmetrical form appears. Sometimes it's not possible to maintain the original symmetry.

Feel free to reply if you need more help with this.

Best regards,

Ricardo Tadeu.

Thank you so much for your response. I got email for Prof. P. Balha. He also respond same type of answer.