Investigating the structures of close packed solids in metal sulfide nanocrystals

This in-class activity is designed to assist students with the visualization of solid-state close-packed structures, using metal-sulfide nanocrystalline materials as a an example system. Students will be asked to visualize and describe both hexagonal closest packed (hcp) and cubic closest packed (ccp) structure types, and isolate the tetrahedral and octahedral holes within each structure type. Lasty, students will be asked to compare and contrast four metal-sulfide unit cells discussed in the paper below.

Powell, A.E., Hodges J.M., Schaak, R.E. Preserving Both Anion and Cation Sublattice Features during a Nanocrystal Cation-Exchange Reaction: Synthesis of a Metastable Wurtzite-Type CoS and MnSJ. Am. Chem. Soc. 2016, 138, 471-474.

http://pubs.acs.org/doi/abs/10.1021/jacs.5b10624

Attachment	Size
Solid State Structure - In-Class Activity.docx	941.57 KB
Crystalmaker file of color-coded layers of hcp	27.92 KB
COLLADA file of color-coded layers of hcp	4.67 MB
Crystalmaker file of color-coded layers of ccp	55.09 KB
COLLADA file of color-coded layers of ccp	3.56 MB
Crystalmaker file containing two layers to look for tetrahedral/octahedral holes	23.69 KB
COLLADA file containing two layers to look for tetrahedral/octahedral holes	1.26 MB
Crystalmaker file of an octahedral hole	41.68 KB
COLLADA file of an octahedral hole	255.14 KB
Crystalmaker file of a tetrahedral hole	39.04 KB
COLLADA file of a tetrahedral hole	137.02 KB
Crystalmaker file of a NiAs Unit Cell	16.63 KB
COLLADA file of a NiAs Unit Cell	447.81 KB
Crystalmaker file of a Rocksalt Unit Cell	26.08 KB
COLLADA file of a Rocksalt Unit Cell	792.7 KB
Crystalmaker file of a Wurtzite Unit Cell	17.93 KB
COLLADA file of a Wurtzite Unit Cell	538.8 KB
Crystalmaker file of a Zincblende Unit Cell	19.46 KB
COLLADA file of a Zincblende Unit Cell	549.77 KB

Learning Goals

In answering these questions, a student will…

...develop stronger visualaztion skills for extended, solid state materials;
...compare the packing sequence of close packed structures;
...locate tetrahedral and octahedral holes in close packed systems;
...count the number of tetrahedral / octahedral holes relative to the lattice ions; and
…determine the number of atoms in a unit cell.

Equipment needs

The use of software - such as the demo version of CrystalMaker (http://www.crystalmaker.co.uk) or StudioViewer (Esko - app stores) - will be really helpful. StudioViewer can be run on cell phones, tablets, or MacOS devises. CrystalMaker is available for both Mac and PC.

Instructions on using Studio Viewer to visualize structures on mobile devices are available in the learning object, Visualizing solid state structures using CrystalMaker generated COLLADA files.

Related activities

An ion exchange method to produce metastable wurtzite metal sulfide nanocrystals

Visualizing solid state structures using CrystalMaker generated COLLADA files

Solid State Models with ICE Solid State Model Kits

Solid State Stoichiometry Online

X-ray Crystallography

Close Packing Activity

Introduction to Miller Indices

Implementation Notes

This learning object was developed at the 2017 MARM IONiC workshop on VIPEr and Literature Discussions. It has not yet been implemented.

This could be assigned for homework, but would likely work better in class with guidance.

Time Required

This will probably take 50 minutes depending on how much work with models you do.

Web Resources

J. Am. Chem. Soc. 2016, 138, 471-474

Evaluation

Evaluation Methods

Evaluation methods could include grading as an in-class worksheet, trading with a partner for peer grading or turned in as an out-of-class graded homework assignment.

Evaluation Results

Currently, this activity has not been tested in a classroom. Please post how your students did!

Creative Commons License

Attribution, Non-Commercial, Share Alike CC BY-NC-SA

Carmen Gauthier / Florida Southern College

I am going to try this activity in class but I have also added stoichiometry questions for the four unit cells described in this activity.

Sun, 02/05/2023 - 13:32 Permalink