1. The Solid State

2. Structures of Solids Section 11.7
Solid structures can be categorized into two broad categories
Amorphous solids have no recognizable structure
Crystalline solids have a definite pattern (order) to their structure

3. Unit Cells
Crystalline solids form a repeating structure made up of individual units that are referred to as unit cells
Amorphous solids do not possess unit cells
We will be discussing 4 different unit cells:
Primitive (simple) cubic
Body-centered cubic (BCC)
Face-centered cubic (FCC)
Hexagonal close packed (HCP)

4. Primitive Cubic Unit Cell
Contains 8 atoms (all located on the corners of the unit cell)
Translates to 1 atom/unit cell

5. Body-Centered Cubic Unit Cell
Contains 8 atoms located on the corners as well as one atom located at the very center
Translates to 2 atoms/unit cell

6. Face-Centered Cubic Unit Cell
Contains 8 atoms located on the corners of the unit cell as well as 6 atoms (one on each face of the unit cell)
Translates to 4 atoms/unit cell

7. Hexagonal Close Packed Unit Cell
Contains 6 atoms/unit cell

8. Determining the Contents of a Unit Cell
Determine the number of Na+ and Cl- ions present in the unit cell for NaCl. A representation of this unit cell is provided
See Sample Exercise 11.7 (Pg. 462)

9. Edge Length in BCC

10. Calculating Density from Unit Cell Data
LiF crystallizes in the exact manner as NaCl. The unit cell is 4.02 Å on an edge. Based on this and the data from the NaCl unit cell, calculate the density of LiF.
See Sample Exercise 11.8 (Pg. 462)