Inorganic Chemistry “Is” the Periodic Table

When asked about the subject of “inorganic chemistry”, my thoughts immediately turn to the periodic table. One of the best online periodic tables is WebElements, an ongoing effort spearheaded by Mark Winter at the University of Sheffield. WebElements was the first periodic table to hit the WWW (in 1993), and can boast almost 50 million page views in the past year. This staggering number is not surprising, for to call WebElements simply a periodic table would be to diminish the true content of this excellent, award-winning effort that also has the distinction of being listed amongst JCE Online’s suggested Web sites (1). Indeed, a recent article recognizes WebElements as one of the six most-valuable chemistry sites on the Internet (2). I would actually be tempted to designate WebElements as the one Web site that every chemistry student should be required to experience at some point in their studies. I shall not dwell on the many features that WebElements has to offer (1, 2) other than to point out that a variety of useful tools are found in the “Chemputer” link. These innovative, yet easy-to-use applications are great time-savers for busy students and include useful verification tools for a number of calculations commonly encountered in the laboratory (such as reaction yields, element percentages, isotope patterns). I would recommend the “scholar” version for high school and freshman post-secondary students and the default “professional” version for those pupils in upper-level post-secondary courses.

Another intriguing example of an online periodic table is Visual Elements, a visual arts and science collaboration supported by the Royal Society of Chemistry. On the surface, Visual Elements is what its name suggests—an expressive, image-driven interpretation of the “number-and-symbol” periodic table that chemists are more used to. Within the subsections for each element are a variety of interesting facts and links to the expected chemical data. QuickTime movies (3) are also featured for the more common elements, but these fall more into the category of “cool” than informative, and require some serious bandwidth to be enjoyed. Where Visual Elements succeeds is in capturing the imagination of the non-specialist; the icon-driven format of the periodic table almost wills the mouse to click and discover what lies beneath. One of the more fascinating visual interpretations is found in “Periodic Landscapes”, where there is a series of computer-generated panoramic models based on various patterns and relationships within the periodic table. This site would be an excellent starting point for high school students or non-science majors at the college level, as the intertwining of arts and science is a refreshing reminder that neither discipline truly exists in isolation. (On a technical note, I found that the Shockwave/Flash version of the site loads much more quickly than its html counterpart (4).)

Molecular Shapes and the Structure of Inorganic Solids

Many students’ recollections of their introductory inorganic chemistry courses would no doubt include a familiar acronym—VSEPR (Valence Shell Electron Pair Repulsion). The Internet contains a vast number of Web pages devoted to this subject; entering the above combination of five letters produces no less than 16,000 hits (5). Not surprisingly, the first offering on the list is from Mark Winter, the mind behind WebElements. These interactive exercises are very well done, and are supported by both static color images and models that can be manipulated in three dimensions (see Figure 1). The latter uses the JMol viewer (6), which has the benefit of providing a dynamic interface without the need for a browser plug-in (such as Chime [7] or Chem3D [8] ). This is an excellent one-stop site for students who are learning about VSEPR for the first time or for those who need a refresher in its fundamental principles and applications.

Figure 1. The geometry of H₃N→BF₃; VSEPR by Mark Winter, (accessed Oct 2002).

Making Matter is a Web site that covers another important topic in inorganic chemistry—the structure of inorganic solids. This site is a subset of the larger Inorganic Crystal Structure Database (ICSD) for the WWW , and presents a clear, concise description of how extended three-dimensional networks of atoms form many important inorganic materials. The occasional mention of crystallographic symmetry descriptors makes the site somewhat less useful for the novice, but this minor complaint is offset by the inclusion of a variety of visually expressive images. A wide range of topics is covered, beginning with how atoms pack in the solid state and venturing into the important categories of perovskites (Figure 2), covalently bonded structures, zeolites (Figure 3), gems and minerals, superconductors, magnets, and the layered structures of lubricants and clays. Students wishing to delve deeper into the structures can do so (quite literally), providing they have a VRML plug-in for their browser (9).

Figure 2. A representation of the basic ABX₃ structure of perovskite; Making Matter by Alan Hewat, (accessed Oct 2002).

Figure 3. A representation of Linde zeolite A; Making Matter by Alan Hewat, (accessed Oct 2002).

Transition Metal and Organo-metallic Chemistry

Transition metal and coordination compounds usually form a large part of any course on inorganic chemistry. John Nash’s Web site at Purdue University is a very comprehensive offering on the subject, and its use of Chime (7) has been noted in a previous News from Online column (10). Although the frames-based architecture is not my favorite for navigation, I can see why it is used—the amount of information and the number of useful features included in this site is massive. Particularly useful are the glossary and molecule library; (almost 300 entries in the glossary, more than 125 entries in the molecule library). Importantly, the framed Web pages enable a student to view the glossary entries while retaining the content in the main window. The Compare Structures section is also quite useful, as it allows for the side-by-side 3D evaluation of the basic structural types encountered in coordination chemistry. A VSEPR companion Web site at contains a number of practical problems to test student knowledge as well as the useful glossary mentioned above. From a technical standpoint, the Chime (7) plug-in is needed to view the embedded structures that form the most powerful interactive elements of the two Web sites. While not a problem for savvy users, I have found that extensive use of Chime may be somewhat limiting to less technically oriented students who use public campus computer labs (which typically do not have Chime installed by default).

The field of organometallic chemistry is well covered by Rob Toreki’s Organometallic HyperTextBook. More than 40 topics currently appear in the index, representing many of the main themes that students are exposed to in senior level inorganic/organometallic chemistry courses. As the name of the Web site suggests, the look and feel is reminiscent of a textbook, but a text that is easily navigable through hyperlinks. I particularly like this site as a useful reference for organometallic experiments—it is very easy to link to the germane sub-sections of the Organometallic HyperTextBook without fear that the students will lose their way (as can often happen with less straightforward Web sites). The site is an excellent example of emphasizing content over gimmicks, an ideal that is easy to lose track of when creating online content. Advanced students will benefit from the thoughtful offline suggested reading lists that are found in several sections. Additionally, several segments have self-test components to quiz student knowledge, for example, an interactive exercise on electron counting. My students have reported it as quite helpful for both writing lab reports and preparing for exams.

Conclusion

The World Wide Web is an excellent source for information on inorganic chemistry—there are many more resources available than have been mentioned here. The Web can be made a little friendlier by suggesting a few well-done and immediately usable sites that apply to the subjects the students will encounter in their studies. Once their appetite is whetted, who knows where the WWW will take them?

Literature Cited

1. Review (accessed Oct 2002)
2. Murov, S. J. Chem. Educ. 2001, 78, 1429.
3. Apple QuickTime (accessed Oct 2002)
4. Macromedia Shockwave Player (accessed Oct 2002)
5. Using the Lycos search engine; search run Oct 12, 2002.
6. JMol viewer (accessed Oct 2002)
7. MDL Chime (accessed Oct 2002)
8. CambridgeSoft Chem3D (accessed Oct 2002)
9. A list of suitable VRML viewers (accessed Oct 2002)
10. Dorland, L. J. Chem. Educ. 2002, 79, 778.