Unit Cells

Simple Cubic

\#of atoms/unit cell: 1

radius (r): a/2=r

coordination #: 6

Body-Centered

\#of atoms/unit cell: 2

radius (r): (a\*sqr3)/4=r

coordination #: 8

Face-Centered

\#of atoms/unit cell: 4

radius (r): (a\*sqr2)/4=r

coordination #: 12

r = radius

a = edge length, cell edge

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What is the volume for all three unit cells?

v = a^3

Corner (position)

1/8 atoms at each position

Center (position)

1 atom at each position

Face (position)

1/2 atom at each position

Edge (position)

1/4 atom at each position