Exam 2 Workbook 1 due Thursday 0214

1
Announcements General Info
Exam 2 Workbook 1 - due Thursday
02/14 Additional Workbook to be handed out - due
Thursday 02/21 No classes Friday -
Holiday! Office Hours Canceled Friday - will
stay in class today until 11am for help Exam 2
next Friday Lecture Solid State
Chemistry Begin chapter 12 section 6 Lab
Report Form handed out during class One report
per team of two Answers written NEATLY in pencil
or ink LAB - complete as much as possible (first
three sections minimum!)
2
Solid State
Amorphous Solids examples glass, rubber,
plastics, charcoal Crystalline Solids
A pyrite B Beryl C Barite
3
The Unit Cell
Unit cell - the basic repeating unit of the
arrangement of atoms or molecules in a
crystalline solid (_________________). Crystal
lattice - the geometrical arrangement of atoms in
a crystalline solid (image below).
This is a cubic unit cell (all angles 90). Other
geometries are possible
4
Terms
Coordination number - the number of nearest
neighbors (atoms) surrounding a particular
atom. Packing Efficiency
There are _ crystal systems and __ types of unit
cells that occur in nature. We will focus on the
cubic system. The cubic system has _ types of
unit cells.
5
Cubic Unit Cells diagrams
Simple cubic unit cell - the centers of eight
identical particles define the corners of a
cube. Body-centered cubic unit cell - identical
particles lie at each corner and in the center of
the cube. Face-centered cubic unit cell -
identical particles lie at each corner and in the
center of each face but not in the center of the
cube.
6
Summary of Cubic Unit Cells
FCC
BCC
SC
4
2
1
Net atoms
4r/(v3)
2r
Edge length
2(v2)r
68
52
74
Packing Efficiency
7
Another way to represent unit cells
Z-diagrams (Not in Silberberg book)

• Slice unit cell into layers, from Z 0 to 1
• A completed drawing of a unit cell HAS TO HAVE
  Z0 and Z1 as the same image
• Draw 2D representation of layers
• e.g. simple cubic

8
Z-diagrams (contd.)
Another example body-centered cubic
9
Determining Formula of an Ionic Solid
Cuprite -- a copper oxide

• O in BCC positions
• 4 Cu atoms in center

What is formula of this compound? Draw Z-diagrams