I have been trying to find information on the crystal structure or phase of solid elemental metals at temperatures close to absolute zero, but I can only find information on there ambient structures. Does anyone know of any sources that would have thermodynamic tables for solid metals at low temperatures or information on the crystal structure at low temperatures? From the little information I have found it would appear a lot of the metals all form a HCP crystal structure at very low temperatures, but like I said I am having a hard time getting any information. I want to make a finite point mass wave equation. m*utt(x,t) = k*(u(x+h,t)-2*u(x,t)+u(x-h,t)) if you let h -> 0 then you get the wave equation but h is the particle separation, and it is small. so with a small value approximation you get m*utt(x,t) = k*h2*uxx(x,t) but I need information on crystal structure and the particle separation.