Exploring Crystal Structures with XtalDraw
Summary
This exercise uses publicly available resources to visualize mineral structures in three dimensions on the computer, including symmetry, the use of polyhedral modeling and linking, and the effects of solid solutions on bonding.
Context
Audience
Undergraduate mineralogy
Skills and concepts that students must have mastered
This exercise comes after a brief introduction to symmetry, lattices, and Pauling's rules.
How the activity is situated in the course
This is part of a sequence including X-ray diffraction, X-ray fluorescence, and a final project on an individual's mineral. This can be easily adapted to be stand alone exercise.
Goals
Content/concepts goals for this activity
Crystal structures and symmetries in minerals.
Higher order thinking skills goals for this activity
Visualization in three dimensions and formulating an understanding of the effects of solid solutions on the lattice.
Other skills goals for this activity
Description of the activity/assignment
At the end of this exercise students will be able to use computer-based software to draw crystal structures and visualize symmetries present in minerals. By varying the way in which atoms or groups of atoms are displayed, they will begin to see how atoms link through bonds. Students will also begin to investigate the effects of variable composition on bonding on unit cell parameters.
Determining whether students have met the goals
Brief free response to each section.
More information about assessment tools and techniques.Teaching materials and tips
- Activity Description/Assignment (Microsoft Word 33kB Jul16 09)