How Do Atoms Arrange Themselves To Form Solids?: Simple Cubic
How Do Atoms Arrange Themselves To Form Solids?: Simple Cubic
How Do Atoms Arrange Themselves To Form Solids?: Simple Cubic
SiO2
Interatomic distance
0
2R
- hard-sphere model
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Simple Cubic (SC) Crystal Structure p
Two representations
of the FCC unit cell
a = 2R 2
R
a
APF = (Sum of atomic volumes)/(Volume of unit cell)
4 3
Volume of 4 hard spheres in the unit cell: 4 × πR
3
Volume of the unit cell: a 3 = 16 R 3 2
16 3
APF = πR 16 R 3 2 = π 3 2 = 0.74
3
maximum possible packing of hard spheres
Grain Boundary
Schematic picture of
amorphous SiO2 structure