1. The problem statement, all variables and given/known data Sodium transforms from bcc to hcp at about T=23K. Assuming that the density remains fixed and the c/a ratio is ideal (1.633), calculate the hcp lattice constant a, given that the lattice constant a'=4.23 Angstrom in the cubic phase 2. Relevant equations I cant find any equations regarding this 3. The attempt at a solution We haven't gone over this in class so I don't even know where to begin.