Initial Publication Date: June 28, 2005

Unknown #3

Download and view the crystal structure data

Right click on Unknown_3.cmdf ( 2kB Dec16 09) to download the crystal structure to your computer. (This file was modified from a CIF file in the Crystal Structure Library provided in CrystalMaker).
Start the CrystalMaker program.
Choose the File > Open command, and select the file you just downloaded to view in CrystalMaker.
Click on OK to generate the crystal structure for viewing. You should see something like this...

Determine the identity of the unknown

Using your knowledge of crystallography and systematic mineralogy, and manipulating the downloaded structure in CrystalMaker, answer the following questions to deduce the identity of the unknown. Check your answers by clicking on the "show answer" tabs which appear with each question.

To see an adequate portion of the structure (not just the unit cell), choose Transform > Set Range, and click on Expand 2 times to extend the structure along all axes by 20%. Click OK.

Next, draw the Fe-O bonds by choosing Edit > Bonding. Click on Add and choose "Fe" under From and "O" under To. Clicking on the box under Info will give you information about coordination. Finally, click on OK to draw the bonds. The window should look like this...