Question

If the critical radius of the nucleaus that first forms on solidification is rought 0.0000003345 cm and the lattice parameter for that material is 0.3096 nm, how many atoms form in the initial spherical solid if the crystal structure is BCC?

Answer 1

First, you need to calculate the volume of the spherical solid as follows (r=0.0000003345 cm=3.345 nm):

Now, if you take into account that a BCC is a cubic crystallographic system, you can determine the unit cell volume:

The, you can calculate the number of BCC unit cells that can form the spherical solid:

Finally, you can calculate the total amount of atoms that can form the initial spherical solid, taking into account that in a BCC crystal system fit 2 atoms/unit-cell.

The initial spherical solid is made up of approximately 10558 atoms.