Sciencemadness Discussion Board

The space occupied ratio of Hexgonal close Packing crystal cell in metal

ilwdx - 10-6-2004 at 04:29

the textbook said it is 74.05% but I got 73.15%.

anyone knows how it is worked out?

[Edited on 10-6-2004 by ilwdx]

Proteios - 10-6-2004 at 08:11

its in text books.... and on the web.

Re: The Space Occupied By Metal Atoms In Hexagonal Close Packed Crystal Structure

JohnWW - 8-8-2004 at 18:06

According to "The Penguin Dictionary Of Curious & Interesting Numbers", by David Wells (1986), the density of identical spheres in an hexagonal close packed crystal structure is pi/3sqrt(2) = 0.7404804.

While all mathematicians and crystallographers "know" that the hexagonal close packed structure is the densest possible packing of identical spheres, as in the pure metals and condensed inert gases, of the 7 crystal systems and 32 crystal subsystems, no-one has been able to rigorously prove this.

John W.