Dear Steve,

the no. of atoms in HCP unit cell i.e. “N” should be “6” instead of “4” given in the manual.

N= (N_C/6)+(N_F/2)+(N_I/1)

where

N_C = total number of corner atoms in a unit cell = 6+6 = 12

N_F= total number of face atoms in a unit cell =1+1 =2

N_I= total no of interior/center atoms in a unit cell = 1+1+1 =3

hence,

N =(12/6)+(2/2)+(3/1) =6 atoms

I also tried to visualize the structure also. I am not able to see a hcp lattice.

Any suggestions?

warm regards

Vijay