Materials chemistry

14 Mar 2020

Solid State Structures tutorial

Submitted by Terrie Salupo-Bryant, Manchester University
Evaluation Methods: 

I grade the Solid State Structures tutorial answer sheet (44pts) in conjunction with the Problem Set to Accompany the Solid State Structures tutorial (26 pts) that incorporates concepts from the tutorial.

Evaluation Results: 

The average score (n=32) is 60pts out of 70 (86%).  Scores on the Problem Set tend to be about 5 percentage points higher than on the tutorial.  Students usually spend some time calculating the length of the unit cell edge, a, in terms of the radius (r) of an ion/atom for each of the basic unit cells.  Commonly they substitute diameter for radius or make errors in their trigonometry (see doi.org/10.1021/ed400367x  for derivation).  They also have difficulty seeing an empty hole which causes their percentage of filled octahedral and tetrahedral holes to be incorrect.  I added Figures 6 and 7 for fcc in order to help students in the future know where to look for the holes.  Visualizing 3D structures can be a challenge even to visual learners.  The average score indicates that manipulating structures on the computer makes them more tangible to students.  Wrestling with the questions is often a group effort and an opportunity for students to explain their thinking to others.

Description: 

This tutorial will introduce students to some of the three-dimensional crystal structures exhibited by ionic and metallic solids.  They will examine the simple cubic, body-centered cubic, face-centered cubic, and the hexagonal closest-packed systems.  To facilitate visualization of the structures at the atomic level, they will use the Crystal Explorer website at Purdue University.

Corequisites: 
Prerequisites: 
Learning Goals: 

After completing this tutorial, students will be able to:

  • Identify and describe basic crystal structures from their unit cells.
  • Describe the relationship between crystal packing and unit cell.
  • Determine whether atoms/ions in a crystal structure are closest packed.
  • Locate tetrahedral, octahedral, and cubic holes in a unit cell.
  • Apply geometric relationships to determine the length of a unit cell edge in terms of the radii of its atoms/ions.
  • Determine the coordination number of an atom/ion in a crystal structure.
Implementation Notes: 

The Crystal Explorer website is a free resource that contains all of the images needed to complete this tutorial.

When I teach my foundations-level inorganic chemistry class, I have students use Ludwig Mayer’s Solid State Structures JCE Software to complete this tutorial; however, the software is no longer commercially available.  It utilizes the PCMolecule application which I am still able to access on newer computers by adjusting the compatibility settings.  The images in the software use the same color schemes as the structures in the Solid State Model Kit.  See Teacher Notes for further information. I don’t have students use the model kits, though I do assemble one or two structures for them refer to if they need. 

Students can complete the tutorial in one lab session or in multiple lecture sessions.  I currently use one lecture session to get them started and have them complete it outside of class as a homework assignment.

Time Required: 
2.5 hours (longer if using the Solid State Model Kit)
8 Oct 2019
Evaluation Methods: 

assessment of students will be preformed by grading their answers to the questions in the activity.

Description: 

This is a 1 Figure lit discussion (1FLO) based on a Figure from a 2015 JACarticle on synthesizing conductive MOFs. This LO introduces students to Metal-Organic Frameworks and focuses on characterization techniques and spectroscopy. 

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

As a result of completing this activity, students will be able to...

  • define what metal-organic Frameworks and Post-synthetic Modifications are
  • understand MOF terminology and notation
  • discover how mass transport and electron mobility effect conductivity
  • calculate energies of electronic transitions in electron volts
  • make connections betweeen diagrams and material sturctures
  • compare optical and microscopy techniques
  • discover the concept of photocurrect and how it could be used in different applications
Implementation Notes: 

Students should be able to complete the activity without any prior knowledge of MOFs, although some introduction to MOFs and UV-vis absorption spectroscopy would be nice.

8 Jun 2019

VIPEr Fellows 2019 Workshop Favorites

Submitted by Barbara Reisner, James Madison University

During our first fellows workshop, the first cohort of VIPEr fellows pulled together learning objects that they've used and liked or want to try the next time they teach their inorganic courses.

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