Diffraction

10 Jun 2015

Web Resources from the 2013 Inorganic Curriculum Survey

Submitted by Barbara Reisner, James Madison University

 

In the 2013 Inorganic Curriculum Survey, respondents were asked about the resources they used when they teach inorganic chemistry. About 20% of respondents selected "other" and provided information about these resources. A number of people mentioned specific websites. This collection consists of the websites submitted in the survey.

Prerequisites: 
Corequisites: 
21 Apr 2015

Community Challenge #3: Solid state structures

Submitted by Chip Nataro, Lafayette College

This community challenge was to come up with problems on solid state structures. Not exactly my area of expertise. In fact, I ofter turn to VIPEr for help when I teach this these topics. I think we received some really great contributions for this community challenge. I am honored to have co-authored a few of them with Maggie Geselbracht. I look forward to using the rest of these in my class in the future.

Prerequisites: 
Corequisites: 
Course Level: 
15 Sep 2014

Fe2GeS4 Nanocrystals for Photovoltaics

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Methods: 

My student led a 20-minute class discussion of this article in the spring of 2014.  The other students in the class were asked to post two questions about the article to moodle before the class meeting, but they were not asked to complete the literature discussion questions due to assignment overload at the end of the semester.

Evaluation Results: 

The six students posted good questions about the article, some of which I have incorporated into the literature discussion. One student asked why Ge was used instead of Si.  (My guess is that Si is too prone to oxidation - it's consistent with redox potentials.)  Another student wanted to know if any articles had been published after this one describing further progress.  At least two asked how the authors could determine that the photocurrent was p-type.

Description: 

I asked the students in my junior/senior inorganic course to develop their own literature discussion learning objects and lead the rest of the class in a discussion of their article.  Student Johann Maradiaga chose this article describing the synthesis and characterization of Fe2GeS4 nanocrystals with potential applications in photovoltaic devices (Sarah J. Fredrick and Amy L. Prieto, “Solution Synthesis and Reactivity of Colloidal Fe2GeS4: A Potential Candidate for Earth Abundant, Nanostructured Photovoltaics” J. Am. Chem. Soc. 2013, 135, 18256-18259. DOI: 10.1021/ja408333y).  The article describes the synthesis in hexadecylamine/octadecene of Fe2GeS4 nanoparticles and their characterization using powder X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis spectroscopy, and photocurrent measurements.  Building on Johann’s original set of questions, I developed this literature discussion, which is suitable for use in inorganic chemistry courses. Many thanks to article author Sarah Fredrick for reviewing the assignment and adding some great questions.

Corequisites: 
Course Level: 
Learning Goals: 

After reading and discussing this paper, a student will be able to:

  • Understand how variable growth rates along different crystal planes result in specific shapes, and predict a resulting shape given a particular set of growth rates
  • Compare the oxidation behavior of Fe and Ge over time using XPS data
  • Describe a photocurrent measurement experiment and compare the photocurrent behavior of p-type and n-type semiconductors.
  • Explain the value of a communication as compared to a longer research article

 

Implementation Notes: 

Students do not need to be experts to understand this article, but previous exposure to solid state concepts including semiconductor electronic structure, solid state phases, nanoparticle synthesis, and capping agents will be helpful to them.  Alternatively, the article could be used to introduce these topics.

This JACS communication is fairly short and written clearly, so it could make a good first literature discussion for students without previous experience reading journal articles.

I have included a large number of possible questions in the literature assignment, but as always, users should feel free to pick and choose from the options and/or add their own.

Time Required: 
45 minutes (approximately)
12 Sep 2014

Maggie's LOs

Submitted by Chip Nataro, Lafayette College
Corequisites: 
Prerequisites: 
12 Aug 2014

A Tale of Two Structures

Submitted by Chip Nataro, Lafayette College
Evaluation Methods: 

I have not used this in class yet. I plan on introducing it for the first time in the fall. I think it will be an in class activity. It might make more sense in a lab or homework setting. I don't have a lab in my fall course, so that somewhat limits my options. Hopefully more details will be forthcoming. I certainly would appreciate any feedback from anyone that adopts some or all of this Learning Object.

Description: 

In this activity, students will compare and contrast two closely related structures, [Pd(dcpf)PR3]2+ (dcpf = 1,1'-bis(dicyclohexylphosphino)ferrocene; R = Me or Ph). They will be required to obtain the cif files from the supporting information of a paper. They will then make a variety of measurments in the two stuctures. These measurements can be made using a variety of different freely available programs. Instructions are provided for Mercury 3.3 and Olex2. Finally, students will be required to provide a rationale for the differences in the two structures. Students are expected to have some knowledge of crystallography, sterics vs. electronics and the trans effect.

 

This material is based upon work supported by the National Science Foundation under Grant Number (1057795).

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Learning Goals: 

After performing this activity students should be able to

1) Obtain cif files from the supporting information of an ACS journal

2) Open the cif files in a program that allows them to make measurements on the structures including drawing planes and finding centroids in rings.

3) Explain disorder in crystal structures.

4) Rationalize how electronics and/or sterics impact these particular structures.

Corequisites: 
Course Level: 
Equipment needs: 

A computer with an internet connection.

Prerequisites: 
Implementation Notes: 

The provided instructions have students search for the desired information using the ACS pubs search tools. Certainly SciFinder Scholar could be employed if access is available. I have chosen to provide directions for making measurements using Mercury 3.3 and Olex2. Certainly there are other options. Of the two, Mercury is far more user friendly which is certainly an attractive option in a classroom setting. However, Olex2 provides esd values for non-standard measurements (e.g. those involving centroids) which Mercury does not do (at least as far as I know). It might be valuable to have groups perform the measurements with different programs and then have them discuss their results. There should be little to no difference in the values, but the differences in esd's could be a valuable teaching moment.

24 Jan 2014

Student choice literature-based take home exam question

Submitted by Hilary Eppley, DePauw University
Evaluation Methods: 

This question was 30 points on a 100 pt take home exam (the year I did this, there was also a 100 point in class exam as well).   I've included the title page of the take home exam as well as this question.   

The grading scale allowed most of the points for the student chosen course content to highlight.   Of the 30 points, 10 focus on chemical information skills, 20 on summarizing the article and analyzing it using concepts from the class.   

Evaluation Results: 

I gave back a number of the exams before I was able to tally, but of the ones I had remaining: 

60% got full credit on the part a (those who missed neglected to include a summary) 

100% got full credit on part b

60% got full credit on part c (those who missed searched by formula rather than connectivity or provided an insufficient explanation of what they searched on 

100% got full credit on part d

On part e, answers varied widely from 7/17 to 15/17, with an average of 12/17 or a 70%.  

In some cases they lost points for just repeating things verbatim from the paper without explaining them to show they understood the concepts.   The main reason for loss of points however was just a lack of effort at picking apart the paper for parts that were relevant to the course content.   

They were able to successfully apply things such as electron counting and mechanism identification in a catalytic cycle, point groups, descriptions of sigma and pi bonding in ligands.   

 

Description: 

During my junior/senior level inorganic course, we did several guided literature discussions over the course of the semester where the students read papers and answered a series of questions based on them (some from this site!).  As part of my take home final exam, I gave the students an open choice literature analysis question where they had the chance to integrate topics from the semester into their interpretation of a recent paper of their own choice from Inorganic Chemistry, this time with limited guidance.  I also included a number of questions that required them to make use of various literature search tools to show that they had mastered those skills.   I gave them a list of topics that they could incorporate, but based on the poor quality of the responses I received, I encourage you to be more specific in your instructions.  I'd love to see some new versions!      

Corequisites: 
Course Level: 
Prerequisites: 
Learning Goals: 
Students will
  • choose a recent paper that interests them from Inorganic Chemistry
  • summarize why a particular paper is important to the field of inorganic chemistry
  • use literature search tools including Web of Science, Cambridge Structural Database, and SciFinder Scholar to find information aobut cited references, structurally similar compounds, and the authors of the paper
  • integrate ideas such as bonding models, symmetry, spectroscopy structural data, and chemical reactivity from class into a detailed analysis of aspects of the paper

The instructor will

  • get up to date on new literature for possible new literature discussions
  • get a chance to stretch his/her own intellectual muscles on some papers perhaps outside of his/her area of expertise
Implementation Notes: 

The students were given the take home exam about 1 week before it was due (but that was during the final exam period).   The format of the chemical information questions were similar to things they did earlier in the class, however the analysis of the paper was much more open ended, giving them the freedom to choose a paper that interested them and to presumably focus on concepts from the class that they felt comfortable with.   I gave them a date range from April 1 - April 30, 2012 for their paper because those were the most recent issues at the time.  If you use this LO, you will probably want to change those dates to more recent ones.   

Time Required: 
at least an hour, possibly more depending on the student
29 Jun 2013

Five Slides About a Simple powder XRD Analysis

Submitted by Rebecca Ricciardo, The Ohio State University
Description: 

These slides walk students through a solid state synthesis with a simple powder XRD analysis. This presentation was made to answer the question “How do I know what came out of the furnace?” for a general chemistry audience, assuming very little XRD knowledge. Specifically this shows using XRD with database searching to determine phase purity through pattern matching.

(This does not cover the fundamentals of XRD, please see related links for that.)

 

Prerequisites: 
Corequisites: 
Course Level: 
Learning Goals: 

Students will be able too:

  • Learn the steps involved in checking phase-purity using powder XRD
  • Learn that all peaks must be accounted for to fully characterize the XRD pattern
  • Be able to use XRD as a simple technique for pattern matching without an extensive background about why it works.
Implementation Notes: 

This presentation has been utilized in general chemistry courses in which students were completing solid state syntheses. The slides were posted on course websites and also presented during lecture in large enrollment courses, in a short amount of time; < 10 minutes. The students were able to view XRD as a tool to determine phase purity of their samples. (Later students went into the lab to analyze their own syntheses with XRD.) In some instances these slides were coupled with other presentations/activities/lab assignments that were focused on how and why XRD works for polycrystalline samples. (These other items are not available to post here, though the links provided as “related activities” are comparable.)

Evaluation
Evaluation Methods: 

Student understanding was noticed in conversations during data collection, with instructor or peer mentors, and at their final poster presentation with peers, instructors and department members. 

Evaluation Results: 

Students had a general idea of why they were using XRD to analyze their samples. Most students were able to report the purity of their samples correctly. Several students did not consider the additive nature of impure samples; that is if two or more phases were present, then peaks from all phases would be present. Some students also did not consider the possibility of peak overlap with multiple phases.

27 Jun 2013

Introduction to Synchrotron Radiation

Submitted by Megan Strayer, The Pennsylvania State University
Description: 

This 5 slides about gives a basic introduction to synchrotron radiation.  Information includes how the particles are accelerated, how they travel to the individual instruments, and where synchrotrons in the USA are located.

Prerequisites: 
Corequisites: 
Learning Goals: 

After going over the slides, students will be able to:

  1. Explain how the synchrotron energy is generated.
  2. List experimental techniques that use synchrotron radiation.
  3. Construct a list of the pros and cons of synchrotron radiation and use that knowledge to determine if a specific synchrotron experiment is worth pursuing.
Implementation Notes: 

These slides can be used to give students an idea of the basic concepts of synchrotron radiation. After going through the slides, a helpful exercise is to give the students an experiment and have them weigh the pros and cons of using synctroton radiation for the experiment versus a more traditional approach. For example, would it be worthwhile to use synchrotron radiation to obtain X-ray diffraction data on 30 nm crystalline particles? How about 2 nm crystalline particles?  Amorphous particles?

Time Required: 
One class period
Evaluation
Evaluation Methods: 

Students could work in small groups to determine what kind of experiments are worthwhile to submit an abstract to a synchrotron source and which experiments would be sufficient to run without the synchrotron radiation.

27 Jun 2013
Evaluation Methods: 

Written responses will be graded as well as an evalution of student participation in class discussion.

Evaluation Results: 

Evaluation results will be added after this learning object has been implemented in a course.

Description: 

This literature discussion activity is designed to highlight the use of different instrumentation and what details can be gained from each instrument.  It should also help the students review their knowledge of crystal structure, types of crystals, and amorphous solids.  The paper is from Chemistry of Materials, 2013, 25, 2394-2403 (DOI: 10.1021/cm303490y).  The paper should be given one week prior to class discussion, ideally after covering some of the instrumentation in class including X-ray diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). 

Corequisites: 
Prerequisites: 
Learning Goals: 

Students should be able to:

  • apply their knowledge of crystal structure, types of crystals, and amorphous solids to scientific literature.   
  • elucidate the hypothesis of a paper.
  • gain a greater understanding of the instrumentation used to determine the structural details of nanoparticles.    
Implementation Notes: 

Currently I am scheduled to teach inorganic chemistry every other year and have not yet taught the course.  I plan to use several literature papers throughout the course to introduce students to the current literature and relate the concepts to the course material we cover. 

Time Required: 
One class period
27 Jun 2013

A Schaaking development of colloidal hybrid nanoparticles

Submitted by Anne Bentley, Lewis & Clark College
Evaluation Results: 

None of us has piloted this literature discussion yet, but we promise to post results as we do.

Description: 

This literature discussion was created at the NSF-TUES sponsored workshop at Penn State, June 2013.  It is based on the article from Ray Schaak’s group (Buck, Matthew R.; Bondi, James F.; Schaak, Raymond E. “A total-synthesis framework for the construction of high-order colloidal hybrid nanoparticles” Nature Chemistry, 2012 4, 37-44, DOI: 10.1038/NCHEM.1195), which Ray presented at the workshop.


The article draws an analogy between traditional organic synthetic strategies and hybrid nanoparticle synthesis.  It is a good introduction to experimental design, nanoparticle synthesis, and common solid state characterization techniques.

Prerequisites: 
Corequisites: 
Learning Goals: 

After reading and discussing the paper, the student should be able to:

  • Draw a reaction scheme of the nanoparticle synthesis, describe the oxidation states of key reactants, and explain the role of oleylamine
  • Apply theory and concepts (HSAB, intermolecular forces, etc.) to explain aspects of the synthesis
  • Describe and contrast the kind of information provided by each characterization technique used, with a detailed examination of XPS and XRD data
  • Articulate the broader significance of the total-synthesis approach for colloidal nanoparticle
     

 

Implementation Notes: 

There are a variety of ways that the literature discussion can be carried out.  Students should be given the article along with the guiding questions ahead of time to prepare for class.  Instructors can choose a smaller selection of the provided questions for a shorter discussion, or divide sets of questions among groups of students.  To show the students the impact of the paper, the class could look up how many times the article has been cited.  (For example, the article was cited 37 times in the first 18 months after publication.)

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