elemations

I'm getting sick of these punny names. "Elemations" is a hybrid of "element" and "elevations", which I use to describe a cityscape plot of the periodic table of the elements used to demonstrate trends among and between the various chemical elements, as below. I chose "elemations" because no other concise, suitably descriptive term was forthcoming. "Periodic cityscapes" doesn't cut it because that name could describe a cityscape plot of any periodically-varying system, for example average temperature against time of year. The nomenclature crisis that led me to resort to "elemations" stems from the clunky name we have for the conventional map of all the known atoms, i.e. from the phrase, "the periodic table of elements," which is commonly shortened to "the periodic table," because "the periodic table of elements" is a mouthful. But strictly speaking, "periodic table" could be used to describe any tabulated periodic data, and although convention and the use of the definite article generally make it clear when someone is referring to THE periodic table, the graphical technique I propose is fairly unconventional and does not readily accept the definite article. There are, after all, many different atomic trends that could be illustrated with an elemation, and hence, many possible elemations.

The number of known compounds of each element, as represented by an elemation.  Click for larger image.

Apologetics aside, the idea is straightforward, and should be clear from the accompanying images. Recently I became interested in making this graph to represent the number of known compounds containing each element in the periodic table. The content and the form of the graph occurred to me simultaneously. It is common knowledge that carbon, nitrogen, oxygen, and the other elements of life have received vastly more attention throughout the history of chemistry than the so-called "inorganic" compounds, but the elemation seemed an effective way to demonstrate just how extreme this bias is. Below, the same data are presented with the z-axis plotted on a log scale.

The same data as above, plotted with a logarithmic z-axis.  Click for larger image.

Here the bias towards organic chemistry is not nearly so obvious, but the fine detail of the s-, f-, and d-block elements becomes much clearer. Some features of note:

Elemations are known in the literature. The folks over at WebElements have produced this one, for example...

A cityscape plot representing the trends of atomic radii.

...which illustrates trends in atomic radii. Note the absence of identifying symbols on the columns and the garish colors. My own elemations were produced in MS Excel 2002; the .xls file can be downloaded here, and can easily be used as a template for making elemations of other periodic trends by simply cutting and pasting into the appropriate cells of the spreadsheet. For example, here is a quick-and-dirty elemation made using the same file, showing the trends in electronegativity:

Electronegativities according to Linus Pauling, plotted using my .xls file.

Thanks are due to David Flaxbart, head librarian at UT's Mallet Chemistry Library, for his assistance in obtaining data from the CAS structure registry.

iamanangelchaser@yahoo.com

2005-2-18

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