Reference no: EM132554258

Unit Cells Use the visualization tool found at https://atom.calpoly.edu/crystal/

Once atoms are stacked into a 3D crystal lattice, the simplest repeating geometric pattern-the unit cell-will usually contain fractions of atoms. While only whole atoms exist in the crystal, the geometric representation of the unit cell will have atoms split between multiple neighboring unit cells. To find a unit cell, we take the smallest repeating pattern and "slice" the shared parts off, to make it look like a cube (here we are exploring cubic unit cells, but there are shapes for unit cells as well). With Unit Cell selected on the left, use the Expansion slider to see how multiple unit cells together makes up an entire lattice. To highlight a single unit cell within the crystal lattice, press "t" on the keyboard to toggle the translucency.

For each of the cubic lattices, answer the following questions.

1. Which part(s) of a 3D unit cell do the atoms occupy (corner, edge, center, face)?

2. What fraction of an atom does each contribute to the unit cell?

3. What is the total number of atoms per unit cell? (this answer goes in the summary table)

4. What does FCC have in common with BCC? What is different? What does SC have in common with BCC? What is different?