April 5, 2010 Letters

Chemis-Tree Traditions

It was a great delight to read the Newscripts column and find out that ours was not the only lab to "repurpose" our equipment during the holiday season (C&EN, Dec. 21, 2009, page 56). Our "Chemis-Tree" tradition began in 1986 and continues to this day. Every year, a new version is constructed. No two trees are ever alike.

All of the colors associated with them are produced by chemical reactions and standard indicator solutions. A brilliant red is achieved in the presence of calcium and magnesium ions using an indicator containing calmagite. The same indicator yields a very nice blue in the absence of the aforementioned ions. Different shades of yellow can be made employing a vanadate-molybdate reagent and various concentrations of phosphate. Bromcresol green in deionized water produces an acceptable green. Altering the pH to the acid or alkaline side gives gold and blue, respectively. Most of these colorimetric chemistries can be found in "Standard Methods."

Perhaps the most challenging and somewhat difficult part is coming up with different glassware configurations and, of course, "balancing" them. Some versions have been more than 4 feet tall. Needless to say, many current and former employees have enjoyed the display.

Edward Robakowski
Newbury, Ohio

The Capitol Dome: Symbolically Relevant

The cover of the Jan. 18 issue of C&EN features a photograph of the fresco in the rotunda of the U.S. Capitol. This work of art, "Apotheosis of Washington," was painted by Constantino Brumidi in 1865. It presents intriguing allegories to past and present activities pertaining to this year's "Congressional Outlook," which appears on page 10 of the issue.

Apotheosis (from the Greek apotheoun "to deify") refers to the exaltation of a subject to divine level. The term has meanings in theology, where it refers to a belief; in art, where it refers to a genre; and, seemingly, in politics, where some legislators transcend themselves to become "holier than thou," rather than E pluribus unum.

Like our Congress, the fresco has its gods and goddesses variously holding out hands or brandishing spears, arrows, thunderbolts, cannonballs, money, and flowers. There are 13 fair maidens, some good guys and bad guys, a horn-blower, a fierce bird of prey, and some horses. There are a few scientists; sundry men, working and struggling; and accompanying women and children, pleading and hanging on. Mercury, the God of Commerce, is shown giving a bag of gold to a financier.

The fresco is filled with rich symbolism: The 13 maidens represent the original 13 states (the ones with their backs turned represent states that had seceded from the U.S.). Six scenes depict allegories of a national concept—war, science, marine, commerce, mechanics, and agriculture. Presumably, these concepts can now be extended to include issues of concern to readers of C&EN: energy and environment, chemical regulation, homeland security, chemical weapons, food and drug safety, economy and budget, patent reforms, and science policy. Climate change is probably still swirling up in the clouds. Notably, health care is absent, but the gods are immortal.

Brumidi spent 11 months completing the fresco; he worked while suspended nearly 180 feet above the floor. Still, it took almost 75 years to finish the entire dome, which was dedicated in 1954. The final scenes depicted in the fresco had not yet occurred when Brumidi began his masterpiece. Currently languishing legislation has its uncertain beginnings and ends as the "artists" dangle above their respective chambers. "Allegory," which means "to speak in public," is a figurative mode of representation conveying a meaning other than the literal. Let us hope our leaders choose not to express their actions in symbols.

Stacy L. Daniels
Midland, Mich.

Naming New Elements

The International Union of Pure & Applied Chemistry has approved the name copernicum for element 112. While Copernicus' contributions to astronomy and Earth's place in the universe are undisputed, I ask myself what his connection is to the periodic table. All the scientists who have been honored with an element named after them have had some connection with the periodic table, atomic theory, atoms, or a means to create new atoms and isotopes.

It is my opinion that this tradition should have been continued. There are plenty of scientists who made notable contributions in this area who would have been worthy of the honor, such as Avogadro, Dalton, Moseley, Aston, Lavoisier, Cavendish, Priestley, and Ramsay, to name just a few. Copernicus has already been honored with a large crater on the moon and an astronomical observatory, which are fitting and proper. Only five unnamed elements are left before the seventh row is filled. Let's follow tradition and name these elements after someone with a connection to atoms and the periodic table.

J. Daniel Marsh
Oak Ridge, Tenn.

Sodium Azide Precautions

Two recent articles refer to the hazards of working with sodium azide (NaN₃) (C&EN, Jan. 11, page 4, and Nov. 9, 2009, page 8). American Azide Corp., a division of American Pacific Corp. (AMPAC), has safely produced more than 9 million kg of sodium azide over the past 17 years. The azide ion is an extremely useful nucleophile that has been used safely for many years at companies such as AMPAC Fine Chemicals (AFC, formerly Aerojet Fine Chemicals). AFC has used this reagent on a commercial scale for more than 50 years in the production of intermediates for the pharmaceutical and defense industries. Sodium azide is the reagent of choice for the production of primary amines, isocyanates, and several heterocyclic compounds and is widely used in the synthesis of a number of pharmaceuticals, including Avapro, Diovan, and Tamiflu.

As with many chemicals deemed hazardous, sodium azide can be safely handled and used in large-scale chemical processes as long as certain precautions are taken (see, for example, Chemical Market Reporter, Jan. 3, 2005, page 267). Incompatibility of sodium azide with certain heavy metals is well-known. However, the reactivity of NaN₃ with acids to form hydrazoic acid is not well publicized.

The formation of hydrazoic acid, and in particular condensation of neat hydrazoic acid, must be avoided under all possible conditions. As chemists and engineers, we should understand the true hazards of the chemical involved and then put controls in place to handle it safely. Finally, we should be vigilant in our education of chemists regarding the safe handling of these compounds, whether in university, industrial, or government laboratories.

Kent Richman
Vice President, Research & Product Development, American Pacific Corp.
Las Vegas

Pearl River Perspective

I thank the authors of C&EN for their continuing coverage of chemistry in China. While I waited years to travel to China, I found C&EN to be a good source of chemical and nonchemical insights about that amazing nation and its people. I recently returned from the long-awaited trip and noted the article "In Pursuit of Clean Water" and its discussion of pollution of the Pearl River (C&EN, Jan. 4, page 14). Having spent several days near a small portion of the Pearl River on Shamian Island in Guangzhou, I can offer some additional images of the river:

• A scenic, tree-lined long park/pathway along the Pearl River in parts of Guangzhou busy with pedestrians and a smattering of food carts
• A river confluence near Shamian Island where there are nightly spotlight, laser, and music shows that attract both land-based spectators and tour boats
• Mornings on that same confluence, where multiple boats and people remove the previous evening's accumulated debris from the river
• Parts of the river (especially the more stagnant narrow channel along the back side of the island) smelling and looking like a sewer drain
• A couple of men swimming in the river near a bridge where the homeless sleep, hanging on to life rings and beverage coolers as they bob in a boat's wake

As Guangzhou readies itself to host the Asian games this November, I hope that it can clean up the chemistry of the Pearl River as well as it has begun to clean up its cosmetic appearance.

Dean Campbell
Peoria, Ill.

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