Hi,

    We built a cobalt boride (Co2B) crystal. If we bulld a unit cell

the ratio of Cobalt to boron atoms remain 2:1. However if we build

a nanocluster the ratio changes with size of the nanocluster and is never

2:1. For example

For simple box nanocluster with 5A X 5A X 5A Co atoms = 12: B atoms = 10 Co:B ratio =1.2:1

For simple box nanocluster with 6A X 5A X 6A Co atoms = 15: B atoms = 15 Co:B ratio =1:1

For simple box nanocluster with 7A X 5A X 5A Co atoms = 18: B atoms = 10 Co:B ratio =1.8:1

For sphere nanocluster with radius 5A Co atoms = 44: B atoms = 20 Co:B ratio =2.2:1

  Is it necessary that the ratio should remain 2:1 for Co2B nanocluster. And if yes how do I build such a nanocluster?

Regards,

Asha