Inorganic Chemistry Teaching Resources

 Chime Radii

Periodic trends in the radii of elements and their ions are a common topic in general and more advanced inorganic chemistry courses. As an inorganic chemist I like to think of the periodic table as three dimensional, involving both elements and their oxidation states. Here is a depiction of radii of elements and their ions as a Chime www page. You must obtain Chime for your browser. Then view this page and try the various options in the right frame. Note that you can also manipulate the image by using your mouse in the left frame. As currently displayed, the radii are those collected in the periodic table database program "KC? Discoverer" for the Journal of Chemical Education: Software". This display was developed using RasMol and the model Chime pages of Eric Martz.

 The color scheme obtained with the top "all radii" button is related to the charge on the atom and atoms with each charge type are presented as a plane and a color:
    +3 ions are red and are the smallest for a particular element. They are furthest forward.
    +2 ions are orange.
    +1 ions are yellow.
    neutral atoms are blue.
    -1 ions are green.
    -2 ions are white and are the largest for a particular element. They are furthest back.
Van der Waals radii (non-bonded interactions) are not included yet.
Use your mouse (left button) to rotate the table and see the planes separately.

The line dividing the two frames can be shifted with your mouse to give more room for the table or the commands. Zoom the table to fit your display. A list of mouse commands is available at the bottom of the left frame. Use a "Back" command to return to the Chime buttons.

Labels can be turned on to identify the elements. This is particularly useful for charges for which there are relatively few examples, such as -2.

Other buttons allow selection of only parts of the periodic table (rows, columns, lanthanides, and actinides) or only certain planes (atomic charges). Only 1 element (Cu) can be selected individually to show the trend over 4 charge states. Rotate these displays 90 degrees with your mouse to see the trend with charge. Columns (groups) or other single elements can be added on request.

There are two buttons that color the atoms by the sections of the periodic table, but do not differentiate by atomic charge. The description of the colors and categories are in the captions to the buttons.

Please let me know if you have any problems, comments or ideas for enhancements. 

Structure Database

This link will take you to a a database of  250 inorganic and some organic structures. They are produced to be viewed and measured with the Chime or the WebLab Viewer. These are all experimental results, and are designed for viewing and study of molecular shapes and dimensions. Possible projects include comparison of measured and predicted bond lengths and bond angles, testing of VSEPR predictions, and analysis of steric influences.

Links of Note

WebElements Periodic Table More Periodic Tables Chart of the Nuclides

VSEPR Tutorials: SheffieldPurdue

Isomers of Coordination Compounds

Atomic Orbitals: San Diego VRMLDarmstadt

Collections of Molecular Models: Okanagan College  Zeolites

Chemistry Teaching Resources A collection of links, especially to graphical images

Last update: January 18, 1999

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